My PC problem.

[Anders]

Edlren, where were you 6 days ago I swapped over to my old CPU yesterday (before reading Eldren’s post) and low and behold, no errors. That description of the error messages in Memtest86 is accurate. So this means that the XP1800 is broken, and not just incompatible with my mobo? Any idea why it appears to work fine at 100 MHz FSB? Memtest86 said the XP1800 level 1 cache was 128K (that’s correct right?), but level 2 cache was “unknown”. However, I noticed that in the box that lists everything just as the computer starts (after the BIOS and RAID detection) the cache was listed correctly.

For anyone interested, before I changed the CPU I removed the Northbridge heatsink, and OMG there was a tiny dab of thermal paste and that was it. Put on some Artic Silver instead, although at the time it didn’t get rid of the errors obviously. Still all those with ABit mobos would be well advised to look under their Northbridge heatsinks. (To remove my heatsink I did have to remove the mobo).

Thanks to everyone for all your help

[eldren]

Sorry - I have no net access during the week (Parent-imposed )
I would say your XP1800 is broken, but there's no harm in trying it with Memtest86 on another motherboard.
It could be that your XP1800 is just really poor quality, so underclocking it makes it stable. Or, it's broken. Either way sucks. :/
Athlons have 128K L1 cache (64K code + 64K data) and 256K L2.

[Anders]

No weekday access bummer, and I thought I had it bad with only off peak access.

I’m thinking it’s more likely broken, because I’m sure I didn’t always have these problems. However I have no other board to test it on, never mind. The codes on it are AXDA1800DLT3C 4146917270343 AIUGA0235MPM, if anyone can tell me if it is good, bad or average, I’d be pleased. I think it’s a Thoughbred A core? Glad I didn't sell my XP1600 pally now.

[Austin]

Originally posted by Austin
... You could disable the L1 and/or L2 CPU caches if the BIOS lets you, perf will suck ... enable if it doesn't help (again you need a working install to test stability with).

Have you tried the above to ascertain whether it is the L1 and/or L2 cache? If so the CPU is faulty and you should get a free replacement either from your retailer or AMD directly if needs be. It could simply be the mobo disliking the 0.13mu Tbred cores though ... or if you o/c'ed it (esp over-volted) that could easily be the culprit of the fault.

For AthlonXP there are 4 key core types:

1. Pally = Hot and always locked so FSB o/c'ing only, XP2100+ likely max.

2. TbredA (yours) = Much cooler and often unlocked so you can also adjust multiplier (mobo permitting). However it has 1 layer less than TbredB/Barton and tops out around XP2200+.

3. TbredB = Not only much cooler but always unlocked and often o/c's like a dream to. Likely o/c XP2600+ to XP3000+ average.

4. Barton = (Basically) TbredB with double the L2 cache for a 5% speed increase clock for clock. That gets you more speed and a higher rating so expect XP2800+ to XP3200+ average.

It should only cost £40 to replace your CPU with a better one (TbredB), just ensure it's TbredB as most (dun=mb-a$$) sites only state Tbred and there's a sizable diff. £70 for an XP2500+ avoids the worry about which core as it is always Barton, reqs 333FSB by default.

[Anders]

Well I bought the CPU second hand from someone on the (RIP) overclockingstore forum, so I think my chances of getting a new one would be slim to none surely, even if it were a level 1 or 2 cache fault?

I didn’t notice an option to disable cache in the BIOS. It came unlocked, which I assumed the seller had done, but I don’t know for sure. As I said before, I had the multiplier up half of one point and that was it, no over-volting or crazy stuff.

I tried to disable cache in Memtest86, the options were: by test, always on, always off. Changing the option just resulted in cache always being “ON” regardless of the option I selected, doh.

Little rant here now. It should be a quick job to swap the CPU, but noooo, the studs that hold the Alpha Pal to the mobo seems to like to turn with the screws, thus meaning I have to remove the whole board just to take it off, $%£&!

Hmm, I’d love a Barton, which would mean getting an NF7-s and new RAM as well.

[Austin]

Well if you allow AMD to assume you are the initial buyer of the AthlonXP and it turns out to be a fault with the CPU then they may undertake an RMA, can't hurt to ask? Otherwise send it to me

No need for a top SktA mobo like NF7-S to get great speed from Barton. All you need is a mobo with multiplier (frequency?) adjustment which most have and at least 333FSB (should easily do 360FSB o/c'ed). Almost all of these 333FSB mobos (eg KT400) should get you to 12.5x166=2.08ghz (XP2800+) or 12.5x176=2.20ghz (XP3200+) esp if you have good cooling and maybe voltage adjustment. 400FSB can help you more though and you may not even need multiplier adjustment (although they shoudl all come with it). KT600 and nForce2 400/ultra400 are key candidates, SiS748 too (but they lack multiplier adj, traditional SiS). www.dabs.com do a Biostar nForce2 400 for £40 and that must be a top choice, you only really lack Dual Channel but that's only about 5% faster anyway and you'll still be ahead of KT600 or SiS748. It is all money though ...