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:D According to this thread post #87 I feel shocked:
http://www.xtremesystems.org/forums/...t=66721&page=4
CAS 1.5 is not working on a64 based systems :confused: ?
Can't believe it - if it is a fake each CAS2 RAM would run 1.5...... :stick:
So guys what do You think about it?
:toast:
Well technically AMD themself says their cpus don't support CAS 1.5. All I can say is supported or not, CAS 1.5 seems to work fine on my system. Some people claim that they get better system performance & stability with CAS 1.5. I will neither confirm nor deny this statement. :D
:D Nice statement - let's see what other experts have to say........ ;)Quote:
Originally Posted by HousERaT
:toast:
It comes from a good source :)
In a way it shows that a64tweaker just reads what the bios sets.
I guess what the memory controller intrepets is cas2.
You also notice it knocks out a bunch of values for other timings
CAS# Latency (Tcl)—Bits 2–0. Specifies the CAS#-to-read-data-valid.
000b = reserved
001b = CL=2
010b = CL=3
011b = reserved
100b = reserved
101b = CL=2.5
110b = reserved
111b = reserved
Row Cycle Time (Trc)—Bits 7–4. RAS#-active to RAS#-active or auto refresh of the same bank.
Typically ~70 ns. These bits are encoded as follows (only 7–13 are valid; all others are
reserved):
0000b = 7 bus clocks
0001b = 8 bus clocks
. . .
1110b = 21 bus clocks
1111b = 22 bus clocks
Row Refresh Cycle Time (Trfc)—Bits 11–8. Auto-refresh-active to RAS#-active or RAS# autorefresh.
0000b = 9 bus clocks
0001b = 10 bus clocks
...
1110b = 23 bus clocks
1111b = 24 bus clocks
RAS#-active to CAS#-read/write Delay (Trcd)—Bits 14–12. Specifies the RAS#-active to CAS#-
read/write delay to the same bank.
000b = reserved
001b = reserved
010b = 2 bus clocks
011b = 3 bus clocks
100b = 4 bus clocks
101b = 5 bus clocks
110b = 6 bus clocks
111b = reserved
cas 1.5 is a placebo.
it doesn't work, but you think it does.
truth is, A64's don't support latencies below 2.
its just creative bios tricks on Oskars part, that can give a sense of what to expect from cas 1.5 or so... kinda like a "simulated 1.5" haha...
I've known this for sometime from a friend online, however, this is the first time I really looked at actual data to support that. interesting.
i hate to tell you guys about this
but in my taiwanese forums, we already found out that CL1.5 is slower than CL2
and even CL1.5 works find, doesn't mean CL2 work in same speed
:D Do You have any screenies for compario ?Quote:
Originally Posted by guess2098
:toast:
If this is true and the memory controller on the chip does have to convert values from the bios to the "supported" memory timings this should be a sticky of what memory timings to set in the bios.
Could even edit the bios before loading to to only allow these values :)
cuz i am not the one who post the pic, i can't just copy and post in hereQuote:
Originally Posted by HARDCORECLOCKER
but i can give you the URL of that thread
http://www.coolaler.com/ipb/index.php?showtopic=55053
:D O.K. - this is gettin' hot - can someone make it a sticky ?
:toast:
I tried Cas 1.5 and found while it was Memtest stable, I had issues with games - CTD, reboots... and Cas 1.5 in Sandra wasn't any faster.
I too feel it's probably a placebo, not working - and probably makes things unstable anyways...
some how i think 1.5 is more stable than 2 under same speed^^"Quote:
Originally Posted by dnottis
I posted this when I came across Geil's upcoming Ultra-X memory on Anandtech - Rated at DDR400 1.5-2-2-5:
"The new DFI nForce4 boards support CAS 1.5 as a BIOS choice, and possibly a few other high-end boards. CAS 1.5 sounds impressive, but AMD tells us that they do not support CAS 1.5 in their on-chip memory controller." - Anandtech
So CAS 1.5 is not of much use :slap: , not for the time being anyway on AMD, but I can't help wondering if/when they'll support it. I sure hope Geil know what they are doing tho. :)
Hmm from my early testing 1.5 was faster than 2. I'll have to revisit this and verify that. But yes according to the AMD .pdf, 1.5 is nothing.
http://www.xtremesystems.org/forums/...id=34463&stc=1
Still, I doubt that Oskar would option that into a BIOS for "simulated 1.5" ;)
well~~ i am thinking that.... if K8 can;t pick up 1.5... then what value does k8 use when we place at 1.5.....
:confused: So maybe OSKAR himself knows somethin' about it.........?
:toast:
When I use 1.5 it's a more stable for me. So I use just 2 unless I'm really pushing my ram to the limits. :)
Geil uses the lower CAS values as a marketing gimmick, leading people to believe they have come up with some new tech that runs at cas1.5. Supposedly these sticks can even run at cas1.0, maybe they should read some white papers. Link
CAS 1.5 sure does look a lot cooler than CAS 2 :p:
I've found 1.5 actually does nothing for me, good or bad.
HCC - Why don't you just run a test to put this issue to rest. Your Corsair can run cas 1.5, so how about a comparison of your own? :toast:
Cas1.5 is not supported, its not setting cas1.5 and its no faster than cas2. OCZ ran tests months ago to see if it was worth releasing VX at cas1.5, upon advice we decided not to as its not actually cas1.5 being set.
Some vx-4000 I bought of opp a little while ago prefers cas 1.5 by over 10mhz, on my 3700+ sandy. So cas 1.5 is no myth in my mind.
Just did a little test run using SuperPI 1M and Sandra Bandwidth.
CPU @ 2.75GHz
Mem @ 250Mhz
CAS 2.0
SuperPI 1M
1st Run - 30.922
2nd Run - 30.965
3rd Run - 30.797
Sandra Bandwidth
Int - 7218
Float - 7142
CAS 1.5
SuperPI 1M
1st Run - 30.921
2nd Run - 30.950
3rd Run - 30.797
Sandra Bandwidth
Int - 7218
Float - 7140
Going by these results imo they are the same as far as performance goes. I still think that in some ram 1.5 adds stability some how. :)
But if cas 1.5 was truly a reality, your memory should clock lower than cl2 ;)Quote:
Originally Posted by haPpydUde
Mabye but some ram just likes low latts. And I to noticed that the preformance was the same pretty much saw some improvments in some 3d programs. Nothing major, but the fact that I can clock 10mhz highier because of it is why I like it.
true but it shows that it is something besides cas 2 so what is it??Quote:
Originally Posted by s7e9h3n
\
________
LovelyWendie
Leave it to OPP to come up with memory that clocks higher @ lower latencies :toast:Quote:
Originally Posted by haPpydUde
It's most likely something besides the memory since the memory itself doesn't recognize cl1.5 and just defaults to cl2.Quote:
Originally Posted by brandinb
Quote:
Originally Posted by TheMeatFrog
those numbers are within variable range. there is no cas 1.5
even at 3Dmark01, CL1.5 is a bit slower than CL2
but only 10 point..... not really can tell the big difference
http://www.coolaler.com/ipb/index.php?showtopic=57781
of course it works! it's all about bragging rights, man, and what looks cool! this is XS after all. what would this place be without the results looking faster? :slap: ;)
:p: But what did they test there here:Quote:
Originally Posted by Eldonko
http://www.tomshardware.com/business...x_day1-09.html
Shown is the older GEIL ULTRA-X and no word about the chips - WB or TCCD.
But even it is TCCD it is an increadeble result - 2.5-3-3-X at 325 MHz !!!
Never saw a RAM doing this........ !!! But again, what exactly did they test there?
:toast:
I have, take a another look at the multi being used. 325*4/5=260Mhz Deception marketing woot.Quote:
Originally Posted by HARDCORECLOCKER
/cheer!Quote:
Originally Posted by bigtoe
:fact:
:D Makes me feel sad but it's true - CAS2 is even faster:
1.5:
http://img295.echo.cx/img295/2509/3576mhz4ur.jpg
2.0:
http://img126.imageshack.us/img126/6539/235843go.jpg
Will check 3D'01 soon......... ;)
:toast:
There are rare cases where cas 1.5 will add a small bit of stability over cas2.0. It's similar to tras=00, it doesn't exist because it's reserved but I know for a fact it adds stability at very high TCCD/5 speeds.
I am not going to attempt to explain the reason for added stability though, I'll leave that to the gurus :)
Thanks for the comparisons by the way :toast:
who cares? cas latency does crap all for performance now anyays.
TRCD and TRP are far more important... although CAS 1 would be interesting.
@HCC,
0.040s in 1M is not really what I would call "faster" :D
CAS1.5 is totally not worth it. Any performance gain some might be feeling is just a placebo effect, really. Some folks few months back started using CAS1.5 and all it does is look. CAS1.5 doesn't have any performance advantage over CAS2.0 and reason is that is not supported by AMD chips ;) Whatever BIOS sets when you switch to 1.5, is not faster than CAS2.0. I used to have comparo screens with 3DM01, few months ago with Neo2/X800XTPE... I can't find them now, though :( But difference was small enough to call it margin of error :)
I just did few SPi 16M runs. 0.141s is definetely not faster :D
SPi16M @ CAS1.5
http://www.xtremesystems.org/forums/...id=34490&stc=1
SPi16M @ CAS2.0
http://www.xtremesystems.org/forums/...id=34491&stc=1
:D Have to thank You mate - You showed me somethin' I did not know.Quote:
Originally Posted by Eldonko
BTW I really feel pissed about the GEIL test done by THG - it is a big amount of :bs: what they did post there........... :stick:
:toast:
a while ago i was playing with that and all results were in margain of error on old CH-5 and old bh-5 chips..........in PI, everest, and hexus pitfast but was all writen down on paper dont have any digital results :)
Indeed. I can get that much variance using the same system. I dare say in the end there will be little to no difference. At least in speed.Quote:
Originally Posted by bachus_anonym
AMD doesn't support CL < 2?
If CL 1.5 is actually 2, then what is CL 1?
Definately not 2.
:D Also Cas2 - even You could set 0.5 it would be 2 cause the mem controller is programmed only to support Cas2 as the lowest setting.Quote:
Originally Posted by largon
All other settings are only "visible" in BIOS or A64 tweaker but at last on ly a fake........ ;)
:toast:
Why does CL 1 cause instant boot if set with A64Tweaker and no boot if set in BIOS?
then why is it that my rig boots fine with cas 2 and 1.5 but doesnt even post with 1.0?Quote:
Originally Posted by HARDCORECLOCKER
Heh no prob. I don't like that test by THG either, maybe if they tried to tell us that the RAM did DDR600 @ 2.5-3-3 people would believe that but saying DDR650 with those timings is basically impossible at this point with any RAM.Quote:
Originally Posted by HARDCORECLOCKER
I think the reason those settings < cas2 are in the BIOS/tweaker is just to allow tweaking for stability, not extra speed/performance. I know if I can get 1 more mhz with cas 1.5 or tras00 I am going to use it :)
later i will try 10 time super pi 1M both CL1.5 & CL2 , today is hot again...........
after my 1M tests, i think CL1.5 and CL2 are almost same. but CL2 is a bit faster
CL1.5
http://img27.imagevenue.com/loc127/th_776_100_2885.JPG http://img28.imagevenue.com/loc167/th_4f8_100_2887.JPG http://img18.imagevenue.com/loc126/th_d17_100_2886.JPG http://img20.imagevenue.com/loc157/th_b84_100_2888.JPG http://img7.imagevenue.com/loc226/th_e13_100_2889.JPG
32.422; 32.458; 32.469; 32.531; 32.453~~ average is 32.4666
CL2
http://img14.imagevenue.com/loc214/th_cf6_100_2894.JPG http://img14.imagevenue.com/loc4/th_ecf_100_2893.JPG http://img39.imagevenue.com/loc5/th_6be_100_2892.JPG http://img30.imagevenue.com/loc193/th_f5d_100_2891.JPG http://img31.imagevenue.com/loc17/th_4d4_100_2890.JPG
32.469; 32.437; 32.485; 32.453; 32.438~~average is 32.4564
you can see CL2 is 1.000314268 time faster than CL1.5 on 1M
but for 32M, CL1.5 will be slower then CL2.... easy to tell.
wish someone can post 10 time 32M result
This may be a little off topic but falls around the same category.
Will DDR2 Ram Latencies ever come down to levels DDR is at now? Will we see DDR2 - 667 2-2-2-5-1T?
I understand that the lower latency dosent effect performance all that much, while higher speeds does, espically for the Intel side of the house. I was just wondering. I mean, lower latencies certainly cannot hurt.
DDR2 667 @ 3-2-2-x is already reality and CAS latency holds nearly no performance benefit (though 3 is slower than 2 or 2.5).
The bios option was given a name, DFI decided to call it cas1.5, it could have been called cas12..infact i may mod the bios to name it cas12, its just a name and nothing more.
It is setting tight latency, just like cas2; but it is not cas1.5.
Cas latency on DDR1 and DDR2 are not quite the same, but the theory of what you are saying is correct. The most important timings are TRCD and TRP, if by setting cas latency loser you are able to set TRCD and TRP tighter (there are other small tweaks also) you have basically made EB ram.Quote:
Originally Posted by STEvil
:( DDR2 and soon DDR3 makes me feel sad - so no company really will force DDR1 further.
No hope for 300MHz 2-2-2-5 on DDR1............ :slap:
:toast:
my dream........ 350 2-2-2-5..... 2.5vQuote:
Originally Posted by HARDCORECLOCKER
With DDR1, that is quite impossible.Quote:
Originally Posted by guess2098
:D Hehe - I just would spend 4V on it.......... ;)Quote:
Originally Posted by guess2098
:toast:
oh, THAT's why you changed your sig? I noticed you changed the 1.5 to 2. What do you mean tight latency? don't 1.5 and 2 options differ by performance means? or they just plain clones of each other? have you tried benching on 1.5 BIOS setting and the 2 one?
:D Right - take a look at post #35.............. ;)Quote:
Originally Posted by DZVlad
:toast:
aaah :) i haven't noticed there were three pages in this topic, sorry :)
but that's strange :) DFI has messed smthing up with that BIOS setting, though the 0.1 sec increase isn't ALL that big.
:D Take Your time and read the whole thread and U will understand......Quote:
Originally Posted by DZVlad
:toast:
Could you tell us in what situation we would notice the benefit of this tighter latency?Quote:
Originally Posted by bigtoe
When you gain some stability using 1.5Quote:
Originally Posted by RaptorRaider
Thank god! finally somebody with the same thoughts.Quote:
Originally Posted by guess2098
Me and my friends here have found about this a long time ago :D
True, for most of the cases, you can easily push your ram's CL1.5 speed as far as the same speed as CL2, and even if CL1.5 works find, doesn't mean CL2 will work in the same speeds. From what me and my friends have tested, CL1.5 was no good, and most of the times even slower than CL2. :) I've also found out that CL1.5 was more stable than CL2 under the same speeds. ;)Quote:
Originally Posted by guess2098
guys
they are the same speed. sometimes cas 1.5 reports faster and sometimes cas 2.0 reports faster, but i will say it again; the numbers are within variation range. cpu speed fluctuates and thats how you get different scores each time you run.
if cas 1.5 doesnt work in the bios, any "performance" differences shot down by benchmarks are now void....Quote:
Originally Posted by bigtoe
:slap:
if it doesn't work, then you cant compare them right now :stick: Do p4's boot 1.5?
One more thing is that after finding the maximum clock with CL2,
then change it to CL1.5 and try to pump it up more, and for most of the
cases you should see that the max mem clock goes up. ;)
This explains why CL1.5 is more stable than CL2 under the same speeds.
(but with less performance)
Just to put this to bed, so to speak...
CAS latency as normally thought of is the latency from CAS going low till when the first data is available during a READ from memory, measured in clock cycles. Side-note is that the memory chips themselves must also support and be programmed for whatever CAS latency is set for READ accesses ;) Here are scope pics showing what you really get for various CAS latencies (READs). The memory was run at 100Mhz (1:2 Divider) to make it easier to see the time delta from CAS to the first data (indicated by the rising edge of DQS after the Read Preamble). Regarding the quality of the signals... this was a quick and dirty session using the "hang-a-wire-instrumentation" method... but you still "get the picture" :p::
Here's CAS set to 2.5 in the BIOS:
http://img211.imageshack.us/img211/7...0mhz8nt.th.png
Here's CAS set to 2.0 in the BIOS:
http://img211.imageshack.us/img211/2...0mhz6aw.th.png
Here's CAS set to "1.5" in the BIOS:
http://img211.imageshack.us/img211/2...0mhz0qt.th.png
Now AMD processor's also allow you to set a different CAS latency for WRITE accesses. It's Tcwl in the BIOS. Here's a pic showing a Read with CAS=2.0, followed by a Write with Tcwl=1.0:
http://img211.imageshack.us/img211/4...1set3uz.th.png
Nuff said :D
Peace :toast:
nice job emc2 those graphics are great. i like how you labeled them thats really cool to see what the memory is "doing"
________
M110 ENGINE
IIRC some P4 boards allowed setting CAS latency to 1... Winbond chips could take it (with some drop in overall overclock), but unsure of others since this was when Samsung TCB3 were pretty popular.
What would be nice is if CAS latencies from 1 to 5 were useable with DDR1 so we could test for an "EB" effect in many different types of chips.
Wow thanks for posting that, cool to see how the RAM really works. :)Quote:
Originally Posted by EMC2
:slobber: Great work !!!Quote:
Originally Posted by EMC2
:toast:
what about CAS read 1.0 ?Quote:
Originally Posted by EMC2
:D UPDATE:
checked the latency with EVEREST - no difference between CAS 1.5 & CAS 2.
:toast:
So.... this may be the reason that i'm getting higher and more stable clocks at cas 1'5 than at cas 2... at least, I get less memtest errors at 1'5 at the same frequency..
i dont get it, whats the reason?Quote:
Originally Posted by krampak
i noticed increased stability with 1.5 too but that wouldnt be possible if 1.5 would be the same as 2.0
Technically, CL2 and CL1.5 might be the same for the current A64 platform.
But at least when you're playing with a DFI nF4 Ultra-D, (SLI-D, DR)
as some people have already experienced, somehow CL1.5 seems to be slower,
and more stable than CL2 on same speeds.
Conclusion, CL1.5 with nF4 series and A64 is nonsense. :)
AMD Athlon 64 3000+ @ 2.2GHz, Newcastle Core, Socket 754, 1.55vCore
DFI LanParty UT nForce 3 250Gb, BIOS 9/14 BETA
1GB (2x512MB D/C Kit) GeIL Golden Dragon PC3200 (Samsung Chips)
RAM @ 220MHz (DDR440), 2.9v, 1.5-3-2-5. perfectly 100% stable.
http://www.tomshardware.com/motherbo...1/geil-08.html
Does AMD Even Support CL 1.5?
Naturally, we also took this question to AMD, to ask them if the memory controller for the Athlon 64 could itself handle a CAS Latency setting of 1.5 clocks. The answer to the question was curt, and referenced a technical document on the AMD-Website that sheds no light of any kind on the subject of supported memory timings. Our interpretation of this response includes the observation that AMD didn't provide any reaction to the topic of supported CAS latency timings. Thus, we cautiously take their admittedly opaque response as a "yes."
Summary And Conclusions: Spare Yourself Of CL 1.5
The only real consequence of using the GeIL DIMMs at CL1.5 timings is the need to boost input voltage to at least 2.9V. Beyond that, this faster mode of operation works inconspicuously. So inconspicuously, in fact, that we had to double-check to make sure our configuration really included the correct timing parameter. Nor could we really prove to our own satisfaction that this parameter was in effect, and thus had to rely on the setting shown in the BIOS and verified by CPU-Z. That's why we suspect that the Athlon 64 barely supports this short CAS latency setting, nor appears to be able to make any effective use of it, either.
Oh well. For me, it's not hurting anything, and I don't need to increase the voltage to get CAS 1.5. @ 200MHz (DDR400) I can run 2.8v, 1.5-3-2-5. 220MHz, 1.5-3-2-5, I need 2.9v. My RAM is warranted to 2.95v anyway--so no biggie.
:D I also need no increase of Vdimm for CAS 1.5 - but who cares if it doesen't perform better than CAS 2 at all........... :rolleyes:
:toast:
People are talking about how there stuff is more stable at 1.5 then 2.0, how can it be the same? Same reason a whole bunch of other wierd random bios settings will make things more stable. It's the same 20ns latency just a different bios setting so that is where you get your different results.
-CaT
hi
i just got the df sli and the ocz vx 4000
i am doing 1,5-2-2-5 at 3,4v
here
the increase of the bandwidth tests is minimal
and i need the same volts that with cl2
its a bit slower in superpi
gives nice pics...and when u sell your stuff u show the pics....lol they love it
:D Hehe - now we finally found a reason for CAS 1.5 - better price to get when selling it to noobs......... :slapass:Quote:
Originally Posted by steelballzz
:toast:
My BH-5 memory sees a stability gain from the CAS 1.5 BIOS setting.
The timing may not accomplish anything for performance, but when it gains me another ~5 MHz (I am sitting at 278 MHz with memtest86 stability), I see it as worthwhile.
Clearly, Oskar has done something for this setting, "CAS 1.5" definitely changes something.
ya but i dont think its a just a DFI thing that "it does something" i got some cheep kingston kvr with infineon ce-5 chips while waiting for my OCZ BH5 and i was just playing with setting it up a bit. With 2-3-2-8 i can run prime for couple hours but with 1.5-3-2-8 i stoped prime at 12 hours, thats on my socket 754 epox, so the thing with 1.5 is deffenetly something up with the CPU mem controler
:D Right - but no suppert by AMD yet. But who knows - maybe further developed mem controllers will in future...... ;)Quote:
Originally Posted by Millyons
:toast:
There will be no ddr in the future :stick:Quote:
Originally Posted by HARDCORECLOCKER
No DDR1....maybe we'll be having this discussion in the future, only then the issue at had would be DDR2 @ CL2.5 :p:Quote:
Originally Posted by dippyskoodlez
:D Right Stephen - but worst scenario: We'll have to discuss whether DDR3 is running CAS 3 or 4.......... ;)Quote:
Originally Posted by s7e9h3n
:toast:
All I know is that the Cas 1.5 setting is faster for benching and did give lower latency times in everest.
But for real world stuff (like giving up all my sleep to play GTA: SA) it makes no diffrerence.