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"Agp Aperture size" influences artefacts of my 3D card !

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May 7, 2007 11:04:24 AM

Hello,

I have OC my P4c 2.6@3.0Ghz .
To do so, I raised the memory frequency to 230mhz from 200.
The CPU and the memory seem to work correctly (no crash to report with the Sandra burn test, and everything is running smoothly since 1 year & half).

The trouble is that I have artifacts with 3D games, but I didn't OC my 3D card.
The smaller the "Agp Aperture size" is, the less artifacts appear.
Actually, the artifacts is likely to be modifying vertex coordinates, because I have a few polys misplaced on the screen (about 20 or 30 polys by second are not displayed correctly, one or more points being misplaced).

Thinking about a synchronization issue between the RAM & VRAM, I raised the RAM latencies to the max ( 3-4-4-8 ) without success.

I have as well raised the AGP voltage (to 1.6v from 1.5), as well as its frequency (to 72mhz from 66), still without any change.

The only thing to remove artifacts is to disable the OC, or to greatly reduce the "Agp Aperture size", but it gives performance issues (which can be terrible with some games).
There are a lot more artifacts when "Agp Aperture size" is on 256 than when it's on 128MB.

To note : I had the same artifacts with my previous card, a Radeon 9700 Pro, but I was thinking it was more or less burnt coz I O/C it a lot... 8)

Anyone would have an idea to try ?
Thanks in advance..!
May 8, 2007 8:56:20 AM

I switched the AGP speed to 4x instead of 8x, and it removed most of artifacts, but it was still not perfect, so I decided to lower the OC, and found out that it was working correctly with a bus speed of 225mhz...

Not perfect solution, but not too bad... :roll:
May 8, 2007 9:44:05 AM

by running your pci/agp busses above standard 33/66mhz you are effectively overclocking your card. put it back to 66mhz and you should be fine.

there should also be a pci/agp lock option in your bios. this will do the same thing

what m/b do you have?
list your hardware specs
Related resources
May 8, 2007 9:57:55 AM

Hello,

here my PC :
MB : Asus P4P800 Deluxe, tried with bios 1019 & 1021
CPU : P4c 2.6ghz (with stock fan)
RAM : Corsair CAS2 400mhz 512MB x 2
Video : Gecube X1950XT (X) Agp (before : Powercolor Radeon 9700 Pro)
PS : Enermax EG465P-VE (FMA) 460W (before : noname 350W)
HD : Hitachi 160MB
Drive : Pioneer DVD

In the bios, for the AGP clock, I tried :
- auto
- 66/33
- 72/36
I didn't notice any change in the number of artefacts by changing this.
I didn't see anything looking like a "pci/agp lock option", except the AGP clock setting.

When I have artifacts, I have a crash very quickly when I run 3Dmark05, although I usually have no or really very few crashes within games.
May 8, 2007 10:41:46 AM

Ok if my memory serves corectly thats a sis based board right?
i have a friend who had nothing but problems with this board.

well even if you dont have an agp/pci lock option you should just stick with the 33/66 option and then, if you want to overclock the card after you sort this issue you can with a software utility. But remember, stick to general overclocking guide limits for your card!

did you have artififacts on the X1950XT before you overclocked? how old is it? what warranty did it come with?

what sort of frame rates do you get with your games?
do you have any way of trying the card in another machine?

3dmark is designed to tax every bit of the card so its understandable that it causes it to crash if there is a problem.
a b U Graphics card
May 8, 2007 11:00:08 AM

Quote:
Ok if my memory serves corectly thats a sis based board right?
i have a friend who had nothing but problems with this board.

well even if you dont have an agp/pci lock option you should just stick with the 33/66 option and then, if you want to overclock the card after you sort this issue you can with a software utility. But remember, stick to general overclocking guide limits for your card!

did you have artififacts on the X1950XT before you overclocked? how old is it? what warranty did it come with?

what sort of frame rates do you get with your games?
do you have any way of trying the card in another machine?

3dmark is designed to tax every bit of the card so its understandable that it causes it to crash if there is a problem.


Intel 865 based, and the 2600's were the worst overclocking chips ever, i got one that didnt get much past 2800, and as for your video card, it seems all too common for ATi cards to go up like that.
May 8, 2007 11:03:01 AM

Hello,

The chipset is an Intel 865PE Springdale, a good one... ;) 
There have been several declensions of the Asus P4P800 (3 or 4, even maybe more with the revisions), and only 1 was very bad, and fortunately it was not mine, which is running smoothly for almost 4 years now... :) 

So far, I didn't OC my 3D card, and I don't plan to.
It's brand new (got it a couple of weeks ago, and mounted it yesterday). It's working very fine as soon as I lower a bit the CPU OC, and the artifacts were exactly the same on the 9700 Pro I had just before.

Unfortunately, even though I think like you that the 66/33 should fix the issue, it isn't, so maybe there's a problem with the BIOS for that particular setting.

The framerate in games looks normal.
3dMark05 scored 6100 in 1280x1024 with FSSA4x where my Amd 64 3500+ with a 7800GT PCI scored at 5100.
May 8, 2007 11:13:51 AM

Quote:
Intel 865 based, and the 2600's were the worst overclocking chips ever, i got one that didnt get much past 2800

The P4c 2.6ghz had a correct OC possibility, although clearly not the best one in the CPU history.
Its possible max OC speed was the same than the P4c 2.4ghz, coz they had the exact same architecture, so the 2.4 was a step better for OC.

The one which was really less good was the P4b 2.66ghz (maybe you mixed up with it ?).
a b U Graphics card
May 8, 2007 11:28:54 AM

Quote:
Intel 865 based, and the 2600's were the worst overclocking chips ever, i got one that didnt get much past 2800

The P4c 2.6ghz had a correct OC possibility, although clearly not the best one in the CPU history.
Its possible max OC speed was the same than the P4c 2.4ghz, coz they had the exact same architecture, so the 2.4 was a step better for OC.

The one which was really less good was the P4b 2.66ghz (maybe you mixed up with it ?).

2.6c was a stepping of its own, the 2.4c had a batch that shared the stepping of the 2.8, 3.0 and 3.2 (and the latter 3.4ghz model), there the same core and share the same feature set but overclocked like poo.

the B series... i have a bunch of 2.4b's that sit at 3.06/667, the 2.66b i had flew over the 3 mark easily.
May 8, 2007 11:58:46 AM

From this overclocking base : http://www.hardware.fr/myocdb.com/categorie27.html (sorry, it's in French, but I hope it's still not too hard to understand)

We can see that the max OC of the P4c 2.4 is 4.467 GHz, and the max one for the 2.6 is 4.315 GHz .
The average OC of the 2.4 is 3.2ghz (on 114 entries) and the average for the 2.6 is 3.3ghz (on 145 entries), which is a bit better.
So it looks pretty similar...

The P4b 2.66 has 48 entries, a max of 3.6ghz and an average of 3.2ghz, which is clearly below both of the P4c (in relative possible gains) ...

If you know any base in English, thanks to let me know about it.
May 8, 2007 2:11:42 PM

Ok apologies for the sis assumption. i just couldnt remember which model asus did that was sis based on 478 skt

so the OP has a good board so i would not look to that for the probs. but instead the gfx card.

test it in another machine if it shows the artifacts then it the card
!