Pass memtest, fail prime?

[beatle]

I'm not sure what to make of this. I had been running my 1700+ @ 2266 (17x133) while I had some cheap PC2100 in with my TwinMos PC3200. I finally got the 2nd stick of TwinMos and now I can't pass prime even @ 204x10. Memtest runs through just fine for over 10 hours, even at FSB speeds of 214, but I can't get my chip stable again. I've tried up to 1.85v with no luck. I generally error out within a couple hours. What is the likely culprit and what would be my best bet for fixing it? Temps seem ok, though system (northbridge?) can reach 34-36C sometimes. Using an Abit NF7-S v2.0.

 

[rommelrommel]

That's very odd...

 

[Match]

My motherboard had trouble once it got to the 200fsb mark. It turns out it was because of a timing issue with the AGP and PCI bus speeds. I had to go into BIOS and adjust that higher in order to get 200fsb and up. Before that, my computer would pass memtest up to 225 fsb, but was unstable in windows (and Prime would fail immediately). I have a different board (ECS L7S7A2) with a different chipset, but perhaps you're experiencing a similar problem. Try playing with various BIOS options to see if anything helps.

 

[beatle]

I wanted to get an idea of what might be causing the problem before I start switching things around in bios. It was my understanding that the chipset is capable of over 200mhz fsb in addition to the AGP and PCI buses being locked @ 66 and 33mhz, respectively. When clocked much higher than 200mhz, prime will fail within minutes, I think I made it almost 3 hours @ 204.

 

[beatle]

Bump, any suggestions? I didn't get a chance to Prime for more than a few hours last night @ 11x200 to see if 2200 works. If it does, I may try 10.5x210. Still confused as to why memtest doesn't kick out any errors anymore. I had an old thread bemoaning my TwinMos, but now I see that it goes through 11 passes of memtest @ 214, 2-2-2-6!

 

[seismik]

I'm having a similiar problem with Prime -- I'm running a P4 2.66B and Corsair XMS RAM, and while I can pass memory testing, play games and do everything I use my PC for without errors, I fail Prime after about 5 minutes whether it's overclocked or not. No idea why this is happening, even when I set my memory timings to very conservative I still have the same issue, however my CPU does get pretty hot with Prime so I've got an SLK900U on order to replace the stock HSF and I'm hoping it makes a difference.

 

[BigJ]

This could be a combination of 2 things.
1) Prime isnt becoming the end all of stability testing for a few reasons
2) Your memtest is testing your MEMORY and only slightly testing the CPU. To help test the CPU during memtest, theres a combination of keys you can press (copyrighted by Thugs) that will help you out.

 

[beatle]

I know the "nintendo cheat code" for memtest. Turns cache on for all tests, runs all tests, and tests all memory.

 

[masterosok]

Yeah im running my 2500 @ 2.4 gHz (218x11) on my ABIT NF7-s rev 2.0 w/ Corsair TwinX 3200LLPT. I runs all the Futuremark benches and my games fine, but fails in prime in a matter of secs.

I don't really like prime to much for a stability test, yes it does tell you if your system is fully stable, however you can still run your pc with normal usage even though it fails.

I really don't mind if my system crash after multiple hours of play, I usually don't run game for more then 3 hours at a time anyway, which seems to work fine, and I will have long been upgraded by the time this CPU even comes close to having issues due to O/C.

The best stability test for me, is just to us my PC and if its starts crashing or acting odd, I know its probably the O/C and just bump it down a lil.

I'm gonna keep an eye on it for now and make sure nothing adverse starts to occur with my O/C, if not these settings should suffice for me.

If you just failing prime, I wouldn't worry about it (I did say I), but if games or other apps start to crash you may wanna up the chipset (NB) voltage to 1.7v is you haven't already, that seem to help me when I was increasing the FSB.

 

[Atif]

LOL, THANK GOD! (sorry, I'm not glad that you're having problems)

I'm not the only one having this problem on the NF7-S 2.0 (go figure) Here are my threads at three forums, they may help you some:

Prime95 Errors @ Abit Forums
Prime95 Errors @ AMD Forums
Prime95 Errors @ nForcersHQ Forum

I have the same memory as you as well (TwinMOS CH-5 PC3200), and got a very nice SLK-800 with ThermalTake Smart Fan on a 2500+.

Peace

 

[masterosok]

If you read the doc that come with Prime that explain that your system very well may run, without you noticing any issues, even thought Prime fails.

Its judgement call, keep the extra o/c and deal with any issues that you get because of it,(to me as long as I can play my games for a few hours with no issues, I'm satisfied).


If you want a 100% stable PC then you may have to change/lower some of your settings. I would say that Prime runs the same everytime, and it may have some bugs but I don't think this is the result of a bug, Prime is great for testing stability, I just don't live by it, cause I don't mind a lil instability as long as its not any major issues, like repeat crashes and reboots, etc.

In my opinion you don't have much to worry about, as long as you don't notice instability in other appz, I don't think that your CPU will malfunction if thats what your worried about, but some people like the peace of mind over the few extra mHz, just not me, crank it up and let it go.

Hell with the prices of the 2500, ($85 on newegg.com) even if this one does malfunction (which I seriously doubt it will) I can just get another. Of course some people can't afford this option.

 

[Match]

One other thing you might check is to run the memory asynchronous from the fsb. Run the cpu at a slower speed, but set the memory at 214 or as close to it as you can. Then if Prime fails, it's probably your memory. If Prime passes, then it's probably something on the motherboard that won't allow the faster fsb speeds.

 

[beatle]

Good idea, Match. I gave this a try last night, using 10x214. It failed memtest with ease, usually within 5 minutes. I am currently testing 200x11.5, which has been running for the past 30 minutes with no problems... temps are just up there @ 57C.

 

[beatle]

Failed after a few hours @ 200x11.5. Some runs went only as long as 2 1/2 hours, one as long as 5. I'm going to encode some video over the weekend... I'll report back if it crashed on Sunday.

 

[THUGSROOK]

sounds like a moboard/cpu instability.
maybe a heat issue during very long operations?
try raising the room temp to make it more obvious.

i know its hard to believe but moboard limitations do exist.

HTH

 

[beatle]

I was hoping it wasn't mb instability, hearing most people hitting well over 200mhz with the nf7-s v2.0. Maybe I'll actually try Insane3d's nb cooling idea.

 

[Atif]

It could very well be a motherboard limitation, but the fact that quite a few people are having this SAME problem on the SAME motherboard lends credence to the possibility that maybe there was a 'bad' batch, because even though there are a few having trouble, not an overwhelming number of people have reported this problem.

I've tried a WIDE array of settings with no luck. 200MHz FSB should NOT be a problem at all, considering that its advertised as officially supporting this FSB on the Revision 2.0 boards. Maybe it's time for an RMA?

On my particular setup, I know heat's not causing the Prime95 failures, as the temperatures NEVER go over 43°C even under LOAD.

Peace

 

[Atif]

Okay,

I TRIED SWITCHING THE MEMORY TO SINGLE CHANNEL... IT DID NOTHING LOL

But, I noticed something. When I fire up Prime95, what was a stable CPU VCore, starts to fluctuate. In the BIOS, I've got the voltage set to 1.85V, now it's a known fact that the NF7-S 2.0 undervolts. However, I notice fluctuations within 0.03 of the starting value of 1.84V (as reported by MBM5) Perhaps this is causing the crash?

Anybody else notice this fluctuation in MBM5 after firing up Prime95? I know I don't have a sucky power supply (it's an Antec TruePower 550) I'm getting the feeling that my particular board may have bad capacitors? (yes/no anybody?) Maybe it's time for an RMA

Peace

 

[Shimmishim]

here's the deal with the ch-5

i've tried two different sticks of ch-5 twinmos from memoryx

both gave me thousands oferrors on memtest using c-2-3-1-2-0

upped the vdimm and it helped but still gave errors

i think there may be an issue with the ch-5 and the abit nf7-s

yeah... no good at all



but anyway... i also heard of someone running prime95 for over 800 hours ~30 days or so (on accident on a computer they didn't check on for a while) and it had errored out on the 865th hour or something....

kind of makes you wonder huh?

i always go for 6 hours of prime... if it makes it, it's good to go!

 

[beatle]

I guess I never replied about the encoding. It did crash while I was away. I'm now running the 2 512 meg BH-5 sticks @ 11x200, 2-2-2-5 with no problems. I can't go any higher than 200mhz @ any timings without triggering Prime95 screwups.