[markodude]

Has anyone else noticed mad variations in the Vcore under full load when running a fast (2.5ghz+) processor??? I am seeing vcore drop from an indicated 1.68 to 1.60 under load??? This is with an Enermax 550w PSU, +12v also sits at 11.67......I am considering taking my C1 out and putting it in my Abit DDR board.....anyone else had probs?

[Wolfen]

Yup. My VCore fluctuates between 1.52 and 1.58 volts running a P4 2.8GHz with an Enermax 431w PSU. Not as bad a variation as yours admittedly.

I'm trying not to worry TOO much about it. :/

The only other major fluctuation is in the +12v line which is running at about 11.55-11.7 volts, all other lines are pretty much bang on the mark. This +12 volt line fluctuates quite a bit and the fan speed for the HSF changes with it. (PSU fan holds pretty much constant at whatever I set it to.)

(All figures provided by MBM5 and the Asus probe utility).

[markodude]

Cheers Wolfen, I am still no further forward though - even 2.50ghz 100FSB crashes in Prime95, Im considering going back to my 1.8A ES chip which was 100% stable at 130FSB...

[Wolfen]

Hmmm.

only things I can think of (you've probably checked all these already)

Mobo bios (mine's 1004a ATM IIRC).
How many fans, etc hanging off that 12 volt line (I have 4 + mobo connector, might try dropping one to see how the voltages change).
Rambus turbo setting in bios.
the freaky semi-automatic cpu/bus/memory speed settings in bios caused me a problem at first as it seemed to get the setting wrong for FSB and mult, but the bios revision fixed that. (it didn't ID the chip correctly and gave huge number of possible multipliers and then mismatched the bus speed to guess at my cpu speed )
What temps are the mobo and cpu running at idle BTW, mine are kind of high (38-40mobo, 45ish cpu), and I was wondering if the VCore was adding to this.

[markodude]

Im going to flash abck to 1004a as I am on 1005beta at the moment....
Rambus turbo setting has never worked for me - how about you? Looks like we have same memory config...
As Im writing this the CPU is at 32c, full load 43-45c (1.525v) it goes to as high as 50ish@1.725v full load which is a bit high, but idle temps stay around 35-40 at 1.725v idle....
I cant believ it doesnt run stable at even 2.50ghz default though, man I have problems

[Wolfen]

I have Rambus Turbo on ATM, seems to be working ok.

Hmmm. My temps have hit a max of 47 mobo, 61 cpu on a hot night last week when loaded to 100% (My room can get pretty hot with the multiple machines, monitors and network hub plus my stereo and at least two people in it.), I'm really beginning to think that getting the silent heat pipe HSF rather than the higher volume one was a mistake.

It hovers around 55-56 full load at the moment, with 47 mobo, mostly due to the ambient temp in my room I think. I need to get a good digital thermometer to get my room and case readings then I might get some beefier case fans if it turns out my room isn't that hot, or a big room fan if it is

Still, It's not as bad as when I first got it all put together and it kept hanging whenever I tried to put it under load for a few minutes. Having the MBM alarm go off and show a CPU temp of 70+ was not a good moment either. I tracked that to the damned video card though, it's fan wasn't running and it was cooking itself and creating a big hotspot right under the CPU.

[markodude]

whoaa that was a close one wolfen!
Im thinking exactly the same as you at the moment, lol I have the Silent Heat Pipe too, and am wishing I had gone for the high volume one .....I broke the fan for my Athlon Heat pipe and had to put a similar one to the P4 Heat Pipe on it - my CPU was no longer stable with 2.05vcore due to the lower volume of air. The Athlon HEat Pipe has a 7k rpm delta on it so I was thinking of getting one of those for the P4, although mounting may be an issue due to the smaller diameter.....
I am curretnly trying to get my mate to get me a big (12") 240v fan that is used in fridges to put on the side of my Athlon case and do away with all the little ones!

[Big Nuttz]

Originally posted by markodude
Cheers Wolfen, I am still no further forward though - even 2.50ghz 100FSB crashes in Prime95, Im considering going back to my 1.8A ES chip which was 100% stable at 130FSB...

I already had to RMA my P4T533 as it would not run my 2.4b stable at stock speeds. Asus had me run memtest86 and I had all kinds of errors.

[Wolfen]

Thanks for the link Big Nuttz, I'll give that a try when I get home from work tonight and then it may be RMA time for another component

Tried Prime95 torture last night, completely unpredictable failure times but never even got to the ten minute mark.

It folds, it plays UT2003 and jedi knight with all the options maxed, but it's far from healthy it seems. I am not a happy bunny right now.

[markodude]

wow wolfen, thats what i was going to ask you to do (run p95) I take it you havent even oc'd your P4 2.8ghz?? I ended up going back to my 1.8A@2.34ghz 130FSB on the P4T-533....
I also have put the 2.50 in my Abit BG7 and got 3088mhz out of it, stable all night, runs burnin test,a ll sandra benchies, 3dmark but still errors in prime95 after about 20mins - processor reaches 60c though so cooling should sort it.
Seems like we may all have to RMA our P4T-533R's then!! Im gonna try this memtest on the P4T-533 with my 1.8A in and see how it goes....
What is stable at the end of the day? If you can run everything you want to and not crash

[markodude]

bahh I dont have a floppy drive - can memtest be ran from a bootable CD!?

[Wolfen]

Nope, it's running stock at the moment.

I'll try to narrow it down to memory, cpu or mobo fault then return the offending part, but it's looking very much like the mobo is the culprit so far. A flakey mobo might explain the weird voltages too.

I can swap RIMMS with a friend to check that, even swap CPU if necessary (he has the same mobo running a 2.533 cpu but has none of these problems) so I should be able to isolate the fault with a bit of wok this week/weekend.

[markodude]

Let me know how you get on mate, where did you get your board from? I hate RMAing stuff to scan.co.uk, they take ages, maybe should send directly back to ASUS??

[Wolfen]

Errr. I got it from Scan too.

If ASUS will take direct returns (and dont just say 'take it to your vendor') then it may be a good idea. I have only the one box though so a long RMA will leave me without a computer

I may try marching into Scan with the mobo under my arm and asking for a new one

[markodude]

ohno another scan customer

At least you are within reach of them, its a 200mile or so drive for me living near London...

The question is..............do you swap it for another P4T-533??? I wouldnt, as mines obviously has the same probs so the whole batch are probably at fault, if not the board design (i850e was never validated for use with the RIMM4200s)

So what board to go for, and what RAM? When I bought it I was going to go for a P4B-533 with XMS3200 DDR, maybe thats an option?? I love my Epox board on the Athlon, maybe the 4g4a is an option, although its a bit low end.....maybe the fact that nobody else makes RIMM4200 boards should tell us somehting??

[markodude]

Ive decided to e-mail ASUS direct today and say that there are problems running C1 steppings, and indeed other very fast P4's on the P4T-533. Im going to try and blag an advance replacement of an A7V8x or another DDR board as I dont want to have to spend time with no PC.
Keep me informed of how you get on with testing/RMAing Wolfen...

[Wolfen]

Well, it's not the RAM. Switched it with a friend and niether of our test results changed (mine still screwed, his perfectly fine).

He has the same motherboard running a P4 2.5 so I'm going to try swapping processors over the weekend as his runs great.

The Asus tech forums are full of rumors about a dodgy voltage regulator on some P4T533 mobos, with a lot of people having problems like ours, so there may be hope yet for a stable replacement from Asus.

[markodude]

I sent this to asus today - have you spoken to scan at all yet??

Dear Sir/Madam,

I am writing with regard to the ASUS P4T-533 motherboard that I have recently purchased, with 2x256MB 32-bit Samsung RIMM modules.

I have owned many asus motherboards over the years and am generally very happy with the quality and stability of your products. I was given the opportunity to build a system to my own specification for mission critical applications and decided to use the P4T-533 as a platform - I had heard it was the fastest P4 board available, and also runs the fastest memory available.

I was running a 1.8A P4 for the first few weeks with no problems, after stability testing using Prime95 the board seems very stable and fast.

I then upgraded the CPU to a new 2.50ghz C1 stepping P4, and started to get stability problems, I have been running RAM at only 800mhz and FSB 100mhz, default vcore, RDRAM Turbo mode off, but I still cannot get stability in Prime95. I decided to look around the forums and see what results other users have had with these boards.

From what I have found it seems that most people running the new C1 stepping chips of 2.50ghz, 2.66ghz and 2.8ghz, are having stability problems with this board. I looked into things a bit more and it appears that the voltage regulators are the problem when supplying so much power to high speed CPU's, the core voltage deviates a lot. I now know of 4 other people who cannot get stability and are having to RMA their boards. In fact the P4T-533 is getting a bad reputation on most hardware websites as being an unstable board altogether, although the P4T-533C does not have such problems. I can supply e-mail addresses of other people with the same problem as me.

I was going to RMA my board to the people I purchased it from, but am also unhappy with their service. They want me to spend up to a week without the motherboard, which I feel is unacceptable considering I have spent over £2000 building a system from what I thought were the best components - not to mention my time building then taking apart and rebuilding the system. My reseller will also offer me another P4T-533 which I do not want as it seems instability problems are there on all P4T-533 boards. I am also unhappy that my reseller seems to be taking the RIMM modules out of the board and selling them seperately. I purchase the board, and then the 2x256mb RIMM's as seperate products.

I am therefore respectfully requesting that ASUS should do something about this problem. I suggest that ASUS should send me an advance replacement motherboard in order to keep my downtime to a minimum. I will now be switching back to an ASUS DDR board, and would consider either the A7V8X or your new Intel chipset board due to be released in early October. I will return the P4T-533 to yourselves on receipt of another motherboard. I will also return the Samsung RIMM memory modules to my reseller to swap for some DDR333 modules for use in the Motherboard you send me.

I look forward to hearing from you in the near future.

[markodude]

BTW Im pretty sure you will find its not your processor, Ive been testing my 2.50 on my BG7 using Prime95. Even at 2.8ghz 112FSB its still rock stable in Prime95. If you put the 2.50 in and its stable in your board, that doesn't mean its definetely the processor as it could be that the board just cant handle such a fast processor. I would test the 2.8 in a board you know that can run stable at 2.8 (ie I know the BG7 is OK at that speed)

[Wolfen]

My friend is running the same board with the same RAM for his new 2.5 P4. I'm pretty sure that the motherboard is the fault as well and will really be looking for instabilities with my mobo when it has his 2.5 on it to confirm my problem beyond all doubt.

His machine will seemingly run Prime95 indefinately.

The voltage regulator being dodgy would fit all the symptoms at the moment, fluctuating VCore (from 1.49 to 1.58 observed now, when it should be 1.525) and unstable under load.

I'll do the test and then mail Asus myself before talking to scan, hopefully Asus will confirm the problem and offer a replacement.