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Just some quick tests on errata 123 and how it effects memory bandwidth.
Sandra with errata 123 DISABLED in bios
http://www.xtremesystems.org/forums/...1&d=1137308195
Sandra with errata 123 ENABLED Iin bios
http://www.xtremesystems.org/forums/...1&d=1137308277
Pi 4m with errata 123 DISABLED in bios
http://www.xtremesystems.org/forums/...1&d=1137308277
Pi 4m with errata 123 ENABLED in bios
http://www.xtremesystems.org/forums/...1&d=1137308277
what is errata 123?
interesting forgot what errata 123 was for ?
just posted this in another thread but this should give you some explanation eva2000:
I was just doing some reading on errata 123 after reading through this and it is suppose to deal with a bug found in some opteron and X2 chips dealing witht he L2 cache,,, if your CPU has it then it needs to be enabled to avoid hang ups or problems when trying to bypass the cache,, but if it doesnt have the bug you get better performance with the option disabled,,
here is the original context:
This BIOS feature is a workaround for the bug. It allows you to disable the cache bypass feature and avoid the bug from manifesting.
When enabled, the processor will not bypass the L2 cache to prefetch data from the system memory.
When disabled, the processor will continue to bypass the L2 cache for certain cache line fill requests. This improves its performance.
When set to Auto, the BIOS will query the processor to see if it is affected by the bug. If the processor is affected, the BIOS will enable this BIOS feature. Otherwise, it will leave it disabled.
If your processor is affected by this bug, you should enable this BIOS feature to prevent the processor from hanging or corrupting data. But if your processor is not affected by this bug, disable this BIOS feature for maximum performance.
^^ yea what he said ! lol
It only applies to dual core, altho I have no way of testing if left on AUTO in bios if it will affect single core memory bandwidth or not.
I've not had any problems with it disabled, but some may so you just have to test !
Well nice findings, Major. I am still wondering why it is enabled when you flash the BIOS? I have to restart.....hmmm to disable it :)
EDIT: Took TIME and you guys posted the findings.
Quote:
Originally Posted by Major
yeah i was trying to determine if you can test it on auto but who knows,,
anyway nice memory scores I must say,,, Im happy usually to break 7000,,,,
is there a way we can test for this bug?
I just ran pi 1m 3x each with it on auto and disabled with my 144 and auto was faster then disabled. It was about 0.12 sec faster on auto. I never messed with it before as I did not know what it was for.
Interesting that it affects single core chips performace tooQuote:
Originally Posted by dogsx2
It's pretty easy to get 0.1 sec difference is 1m so I don't know if it is fact or just normal. 32m would be better and really show if it is faster or slower.
kinda makes sense, if it's simply bypassing the cache to go to the ram, it'll do the same if enabled or disable for either dual or single core cpu's :DQuote:
Originally Posted by Major
I was just under the impression that it was a X2/DC fix, didn't really think about it being enabled on single core.Quote:
Originally Posted by ozzimark
Under which options in the BIOS is this? I can't search now, as i'm still priming :D
aahhh tht feeling of waking up in the morning to find your PC is still priming away :DQuote:
Originally Posted by K.I.T.T.
Nice find Major, will give this a go with my Opteron 146 and report back.
No....I woke up at 5.00 am, just to get start priming. Core 0 failed twice last night :nono:Quote:
Originally Posted by mongoled
First time after 1 hour, 26 mins and then i quit and restarted both cores and it failed again at 2 hours, 3 mins :stick:
Anyway, seems to be going well now :) Imroved my PWM cooling a bit and its been dual priming for 3 hours 45 mins and still going strong!! :woot:
I set this option to auto in the bios and it sticks....so I need it enabled. This is on a single core Opty 148. The difference is minimal, but hey, whatever. :toast:
hmm this is interesting I'll give it a go on my 148 when I get home and post results, at a lan right now :)
Well here are my results, settings in sig, msconfig used to disable all services except MS ones.
SuperPI
Errata123, Status: Auto
http://img488.imageshack.us/img488/3...3autopi8ws.gif
Errata123, Status: Disabled
http://img488.imageshack.us/img488/6...abledpi5qw.gif
Sandra
Errata123, Status: Auto
http://img488.imageshack.us/img488/6...utosand7ny.gif
Errata123, Status: Disabled
http://img488.imageshack.us/img488/7...ledsand7ne.gif
My results are inconclusive, but as others have mentioned, we need to find out a way to see wht AUTO enables for our systems. Then we can see if there is a difference.
According to that article, setting it to auto and then rebooting willl let you know if you need it. It accesses the cpu and if it needs it, it'll stay auto.
Hi! What is your cpu? Real 280?
How to OC to 32xx? And what mainbaord you use?
Thanks.
Opteron 180 Engineering Sample, just programed as a 280 since it came out b4 the release of the 180Quote:
Originally Posted by linhvndiy
See sig for rig details
even running on single core, I'd found the Errata 123 Enhancement stabilized my Opty 148 at higher overclock, do a search on Microsoft database it has a white paper explaining the relation between this feature and the Windows kernel... ;) by the way, mine take a bigger bandwidth hit to have it enable on XP SP2 wherea not as much with SP1a :D
Very interesting and thanks for the heads up, I'll try a few tests and see if there are any meaningful differences :)
where is this option in the bios ?
advanced chipset
Here's the facts on Errata 123 (easily found on AMD site in the whitepapers):
1). ONLY applies to dual core AMD processors
2). ONLY applies at low speeds (AMD, comment on what a low speed is, lol)
3). Affects L2 cache hit/miss operations and can lead to data corruption
4). A fix in the works, this won't be an issue on new rev processors (might not even be an issue with new CPUs now).
-FCG
What about Errata 94? So just set to auto, reboot then go back into BIOS and if its still on AUTO it needs it?