Tref values

[flexy]

astaris, great research !!!

we should write to the coder of a64tweaker so he corrects how he reads the tref in a64tweaker..because this is obviously wrong !

Btw. any other way to read this register besides RMMA ? I mean the whole 5 bits so i can doublecheck whether everything is right.

Your table makes a lot of sense !

thanks !

[burningrave101]

Would 1024MB modules be 3.9us? Everest is reporting them as 7.8us but that doesn't make much sense if 256MB are 15.6us and 512MB are 7.8us.

And have we concluded an effective way of calculating a CORRECT tREF value yet? Is it MEMCLCK ratio x refresh rate (200Mhz 1:1 x 3.9us)?

[astaris]

256 MB single side memory modules can be either 7.8 us or 15.6 us, it depends on the number of rows in the chips: 4096 rows chips have a refresh rate of 15.6 us, 8192 rows chips a refresh rate of 7.8 us.
1 GB double side memory modules can be either 8192 rows (7.8 us) or 16384 rows. In this case often the chips refresh two rows in one refresh cycle, so the refresh rate is stil 7.8 us.
In the end the best way to know the refresh rate is to look at the spd of the module.

[burningrave101]

And after we find the refresh rate we just multiply that times the current MEMCLK divider such as (200Mhz 1:1) for the ideal tREF setting?

[metro.cl]

i tested all of the trefs and wrote down my results on a excel sheet if someone is interested.

i tested: 1 sp8m, 1 3dmark01, 10 passes test n5 memtest and 4 passes test n8 in memtest. (i wrote bandwith, socres on 3dmark01, time in super pi and sandra bandwith).

then the trefs that passed all of the above tests i runned 16m of pi, 3dmark01 and 3dmark03 and then the ones that passed 16m on super pi i tested them with sp32m, now finally with only 3 trefs that passed all of the tests above i'm priming.

So if it helps let me know and i'll upload it or email it, is with some g.skill le 2x512mb tccd431 at ddr600 2.5-4-4-8 i have all the other settings on the excel sheet.

[Vapor]

metro oc....that would be awesome....PLEASE upload it!!

[metro.cl]

well here it is, sorry for the hosting only one i knew. im still testing prime95

http://rapidshare.de/files/3298036/tref.xls.html

if you need sreenshots i have some but not for every test

[Vapor]

For other people...valor = value
pasadas = passes (I think...it literally means happenings, IIRC...took spanish for two years but never paid attention)

[metro.cl]

For other people...valor = value
pasadas = passes (I think...it literally means happenings, IIRC...took spanish for two years but never paid attention)

thats right, is kinda easy

any question just ask, im still priming with tref 1032 more than 1 hour still no errors

[Vapor]

The more I look at it, the more impressed I am with this table...WOW!



A lot of effort has gone into this...tremendous to see that only 5 survived SPI 16M and only three of those survived 32M!

[Vapor]

Say 1032 and 1168 both pass infinitely for P95...will you see which can clock higher or which can also take tighter timings to find which works best at ~300MHz? Not sure if you can tighten much up, maybe trc or read to write, but it may be worth a shot to see if either can take the added heat.

[metro.cl]

Say 1032 and 1168 both pass infinitely for P95...will you see which can clock higher or which can also take tighter timings to find which works best at ~300MHz? Not sure if you can tighten much up, maybe trc or read to write, but it may be worth a shot to see if either can take the added heat.

i'll try more tweaking later, still no errors on tref 1032.

[amrgb]

Thanks very much for your hard work.
It should have taken you a long time to fill such a large sheet.

I'll give a try with your best Trefs and my LE's. Let's see if I can get some improvement. At the moment I'm using 2336. I've reached this value with a similar process to yours. However since I my memories were not on the edge of stability, I've found several Trefs that passed the tests. Unfortunately I can't remember whose Trefs worked for me, since I'm not, by far, as organized as you.

I'll report my feedback as soon as possible.

[EMC2]

Well i don't know why on the bios you have these odd settings, 16, 32, 64 and 128. But i'm sure that:
16 -> 10111
32 -> 01111
64 -> 00111
128 -> 11111
Now these settings are all undocumented and maybe for these values of the Tref register we have different refresh rates, but hey here i made some hypothesis and there's no way to test the real refresh values.

Well.... actually there is a way to test/verify the Tref values While I had my DIMMs instrumented anyway, I did The values for the first 3 sets of TRef in the BIOS are fairly close, including the odd low settings.

The BIOS values are the number of MemClocks between refresh cycles (+/-10%). Divider, multiplier, etc. do not matter... only the actual MemClock period... verified for all pre E-rev A64s.

So:: (1 / MemClock) * Bios_Tref = Refresh Period (+/-10%)

Measured actual TRef values(+/-1 clock) in thumbnail below, along with a table for 200Mhz to 300Mhz MemClock, refresh values in uS.

Peace

[ic3m4n2005]

So it's best to stick as near as possible to e.g. 7.8uS ?

[MikalCarbine]

I noticed at 200mhz, with my 2x512, when tRef is set to auto, it defaults to 3072 3.9us. I am thinking that the Platinum kits TOGETHER (the 2x512) is 3.9us, not 7.8

Who knows though, I have no clue about all this tRef stuff.

[RyderOCZ]

Measured actual TRef values(+/-1 clock) in thumbnail below, along with a table for 200Mhz to 300Mhz MemClock, refresh values in uS.

Peace

Very nice and very helpful...thanks

[EMC2]

Very nice and very helpful...thanks

If you really mean that... you can send the complimentary 1GBx2 kit to....

[Monge]

EMC2: Thanks for your chart
I did notice when I set Tref to high eg. Tref=4708 at 264MHz@3.4v it gives me error in memtest86+ #2. When I use Tref=2048 the error in #2 is gone.

[AndrewK]

One thing I've noticed in my limited play with tref values so far.

On my 2X1gig patriot, and my abit av8 board, the values in a64tweaker are done 200mhz/3.9us etc. In that style.

I've found that the 200mhz/1.95us setting for some reason scores roughly 2000 less than most other values in sandra memory bench. I haven't literally benched them all, but i tested a few values with the refresh at 7.8 and 15.6, as well as some other 1.95 and 3.9 values, and they all netted about 6100-6200 as a sandra score. Yet 200mhz/1.95us scored a mere 4000. It doesn't make much sense.

I've also found that 100mhz/3.9us seems the best on my patriot. Its one of two to successfully do 32M SP with my current settings, the other one being the above mentioned setup that has less bandwidth.

-Andrew

[JfRsQ]

Look at the screenshot, which one you think is giving me the Real Tref

A64 tweaker is showing 133Mhz, 1.95us while RIghtmark util showing it at 7.80 us ? The refresh rate (tRef) was set to 1168 via bios

[yasoumalaka]

I'll share a few of my questions and thoughts on this.

First 1.95us, 3.9us, 7.8us, 15.6us is it that if these are lower the memory will run more stable?????????

Does memory size effect this setting???????

How does command rate affect tref??????

Also I believe once you figure out the refresh time you want to run at you complete this equation [refresh time in us]/[1/fsb] and then select what ever tref is closest to that number.

[yasoumalaka]

What do you think???? Is this right?

[fareastgq]

the trick isn't to set it too high or too low, it's to set it as close as possible to optimal so it's fast but u don't error, only way to do that is test it.

[yasoumalaka]

How do you suggest selecting the refresh period 1.5, 3.9, 7.8, 15.6? My bios setting are relative to cycles and frequency is involved in my calculation so I think it will get me close to optimal, but I'm not sure because I got it from other people's posts.