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View Full Version : Where is my bandwidth going???


Cornelious0_0
05-24-2005, 02:00 PM
I've been struggling with something for awhile here now.....seems I'm missing something when it's coming to my GSkill and DFI Ultra-D.

Check out this pic from the "TCCD DDR600+ DFI nF4 Ultra/SLI guide".....

http://img179.echo.cx/img179/5557/300mhzdcgskill1gblesandra7ew.jpg

Now take a look at mine.....

http://img214.echo.cx/img214/8221/ramissues4hv.jpg

Does anybody have ANY ideas as to where my 200MB/s is going? It might not seem like a lot to some people, but a buddy of mine with the same board and some OCZ rev2 is hitting 8GB/s at 300x9...and I'm stuck at 7612-ish.....and my SuperPi 1M time at 317x9 is almost identical to his at 300x9...both at about 30.7s.

This is really starting to bug me, and any help would be appreciated.

EDIT: Just double checked, his Pi time at 300x9 is roughly 30.700s...and mine is 30.078s......not as close as I thought, but you'd think with an 18htt difference in my favor I'd be up by more then .622s.

EDIT: Just also noticed that the reference pic is with 1GB of ram and mine is with 512MB.....while it is a difference, could it be accounting for that much bandwidth? Regardless.....there's no reason why I shouldn't by leading my friend by more then .622 seconds in SuperPi with an 18htt difference.

[timko]
05-24-2005, 02:41 PM
Many people that have moved from Winchesters to Venice/San Diego have noticed approx 200Mb/s drop in Sandra. The TCCD guide you are referring to would have been completed before Venice/San Diego arrived and as such scored better.

Why the drop with new CPUs? Apparently it's AMD's way of making their mem controller compatible with a wider range and types of RAM. To achieve this, they've most likely relaxed the controller a bit so that it isn't as agressive and in the process knocked of a touch of bandwidth too :(

Cornelious0_0
05-24-2005, 02:45 PM
']Many people that have moved from Winchesters to Venice/San Diego have noticed approx 200Mb/s drop in Sandra. The TCCD guide you are referring to would have been completed before Venice/San Diego arrived and as such scored better.

Why the drop with new CPUs? Apparently it's AMD's way of making their mem controller compatible with a wider range and types of RAM. To achieve this, they've most likely relaxed the controller a bit so that it isn't as agressive and in the process knocked of a touch of bandwidth too :(

hmm, that does make sense.....the guide was written using a Winny, and my friend that I've been comparing scores to is also not running a Venice...hmm...do you still think that the core/memory controller difference could be accounting for why he's only behind me by .622 seconds in SuperPi 1M with 18 less HTT?

[timko]
05-24-2005, 02:53 PM
The HTT speed definitely plays a part in SuperPi times and it isn't totally dependent on overall CPU speed alone.

Previously on my rig with 16Mb SuperPi...

10 x 240 = 2.4Ghz --> 14m07s
9 x 266 = 2.4Ghz --> 13m59s
8 x 300 = 2.4Ghz --> 13m41s



SuperPi 1Mb times are so small the differences between different PCs are harder to measure. Get your friend to run larger values like 16Mb or 32Mb and then compare them to your own :)

Cornelious0_0
05-24-2005, 02:55 PM
']10 x 240 = 2.4Ghz --> 14m07s
9 x 266 = 2.4Ghz --> 13m59s
8 x 300 = 2.4Ghz --> 13m41s

I know how it works.....but we're both doing 9x on the cpu and my htt is simply cranked 18MHz beyond his.....doesn't make as much sense as if one of us was at 8x or something else.

ozzimark
05-24-2005, 07:46 PM
probably single sided 256mb sticks? if it is, the difference is probably from bank interleaving.
also, i get just as much bandwidth on my newark as i did with my clawhammer, and newark is a revE core, just something to think about ;)

Cornelious0_0
05-24-2005, 10:13 PM
probably single sided 256mb sticks? if it is, the difference is probably from bank interleaving.
also, i get just as much bandwidth on my newark as i did with my clawhammer, and newark is a revE core, just something to think about ;)

K, so you're saying that it's probly not to do with the cores then.....or are there any other performance/capability differences between the mem controllers on the Venice and SD cores that I'm not away of?

I am running two single sided 256MB sticks.....how is the difference probly from bank interleaving...anything I can do?

Sry for sounding like so much of a newb, but this is my first A64 setup after being an Intel guy for a good while and I never had fun options like this with any of my s478 boards. ;)

goatman
05-24-2005, 10:23 PM
you got an Ultra-D, aye?
if u scroll down it the memory setup doozy whatsit in the bios u got the bank interleave option (enable or disable). I run 2x512 and i noticed a performance trend. 2.5-4-4-7-1 with bank interleave off performs similar to 2.5-4-4-7-2 with bank interlevae on. having said that, running at 2T and bank interleave off makes my mem bandwidth quite remarkably stinky. the obvious choice is 1T and bank interleave on.

don't worry, LOL, other AMD boards don't have half the bios settings the ultra-D has.

ridikolous
05-24-2005, 10:24 PM
the same thing happen to me on my newcastle 3400... i lost 150mb/s... i replace my nc with a 3200 dtr... den sold the dtr and popped back in my new castle.. clear cmos... i check my bandwidth at same exact settings... my bandwidths were missing... tried all types of bios even went to the old bios... my bandwidth is still missing as of right now. i dont know what to do to get it back..

Cornelious0_0
05-24-2005, 10:39 PM
you got an Ultra-D, aye?
if u scroll down it the memory setup doozy whatsit in the bios u got the bank interleave option (enable or disable). I run 2x512 and i noticed a performance trend. 2.5-4-4-7-1 with bank interleave off performs similar to 2.5-4-4-7-2 with bank interlevae on. having said that, running at 2T and bank interleave off makes my mem bandwidth quite remarkably stinky. the obvious choice is 1T and bank interleave on.

don't worry, LOL, other AMD boards don't have half the bios settings the ultra-D has.

No offense, but what you just tried to tell me had really no relevance whatsoever to what I'm trying to figure out...no kidding the obvious choice is 1t and BI on.....and? :stick:

goatman
05-25-2005, 03:45 AM
No offense, but what you just tried to tell me had really no relevance whatsoever to what I'm trying to figure out...no kidding the obvious choice is 1t and BI on.....and? :stick:
>>how is the difference probly from bank interleaving...anything I can do?

:fact: