Dots on screen during POST

[Ray Proudfoot 8,960]

I've recently built a new PC (Syatem 1 in my sig) but during POST the screen is filled with dots arranged in blocks of 4*4 when the first messages appear. When the screen blanks for a second or so and the next messages appear the dots change to vertical dotted lines.When the Windows XP logo appears they revert to groups of dots 4*4 less bright than originally and as soon as the Desktop appears they all disappear and thereafter the display is absolutely fine.I've Googled the problem but can't find what might be causing it. This problem wasn't present when I first powered it up after building it so it could be down to either something I've changed in the BIOS or perhaps a component is faulty.I should also add that if I go into the BIOS and stay there for a minute or two the screen then clears. I'm not sure if it's a problem with the power supply, mobo or graphics card. Perhaps it needs to warm up for a minute or two?The fact that it's totally stable for hours even when running FSX which is hammering everything suggests there's no problem but clearly I shouldn't be getting this screen problem at startup.If anyone has any ideas or suggestions I'd appreciate it. All the kit is still under warranty but I need to identify which bit is faulty, if indeed anything is.It was suggested to me in another forum that I run memory and video stress tests. I've run Memtest and it did report errors. I'm now running a video stress test and after 50mins it's still fine. There is another 6 hours to go though.If the video stress test ends without problem it is likely that I have a bad memory module. With them being matched pairs can I run the system with just one stick to see if I can identify which module is faulty? They both need to go back if one if faulty but it would put my mind at ease that the 3870X2 is okay.Thanks.

[Guest baksteen33]

Hi Ray, maybe the cable or heat? Some mainboards are sub-optimal for X2s as far as I would dare to judge. When the RAM slots are too close to the first PCI-e slot, one of the X2's GPUs is normally right under the RAM slots after all. Good luck and kind regards Jaap

[Ray Proudfoot 8,960]

Hi Jaap,Thanks for your reply. The 3870X2 is a double-slot card and the fans are enclosed within the case. There are slots at the back of the card to allow heat to escape. Very little heat gets into the case.The other reason I don't think it's a heat issue is that it only lasts for a minute or so after which the screen becomes clear. A cable problem would show all the time I think and it doesn't. After the first minute or so (whether in the BIOS or in Windows) the screen clears and the problem never shows itself again.I ran a video stress test overnight and it reported no problems. The fact that the RAM test reported problems suggests a bad memory module but if that's the case why does it never cause a problem when running FSX?But, this morning the PC didn't fully boot into Windows. It gets so far and then the monitor loses the signal. A reboot does then load Windows but with the warning screen that it didn't load properly. Could this be a sympton of bad RAM as the RAM test suggests?I'm going to remove on eof the matched RAM modules tonight and see what happens. If the problem is still there I'll switch to the other module. That may prove it's a bad RAM module.Cheers,