Hd5770 Low performance

Hi!

First of all I want to thank everyone in advance.

I just bought an ASUS HD5770 and it's installed and working with latest catalyst, but I get some really low ratings on 3dmark06 and low frame rate on Modern Warfare 2 (multiplayer mainly, when playing with everything on top at 1440x900 the game gets really choppy). I'm getting almost the same performance I used to have with my old 8800GT.

I thought I could play MoW2 at maximum settings with that video card, so I guess the rest of my computer has something to do... My motherboard, Ram and processor are quite old, so, can that be the reason? I can't get all my Hd5770 to work with my pc?

My specs are:

Asus Striker Extreme with nForce 680i (Bios revision 1004, from 03/05/2007)
Intel Core 2 Duo E4300 @1.80 GHz
2GB DDR 2 Corsair (2 modules on dual channel)
Asus HD 5770 1GB on PCI-Express x16
600W Nox Urano

I can post some pictures of CPUZ, GPUZ and 3DMark 06 if you need them. I have been thinking about updating the motherboard bios, but I'm not sure if it would really improve anything.

Also, It worries me specially becouse since I installed the new HD5770 the systems takes around a minute to get to the first "bip" and the bios screen. With my old graphic card it only took a few seconds, so I was wondering if there's something wrong with the graphic card.

Thanks a lot again.

Sounds kind of like a CPU bottleneck if your getting the same performance as your old 8800gt. Seems alot of other people could get their 4300s to atlest 2.5+GHz.

Thanks a lot for the advice.

I'll try ocing it a bit and see how it works.

Also, how can I check the video card is not sharing a +12V rail?

A "rail" is a "Cord" from the PSU?. I mean, right now I have the following things plugged:

-One cord that goes to the motherboard (the big one )
-One cord that has 2 small ends plugged on the motherboard.
-One cord with 2 fans plugged
-One cord with the DVDRom and the floppy
-One cord with only the video card

Is it ok??

Also, when I OC it a bit a get better results on 3dmark06 (more then 1k points more when OC 15%), but, although 3dmark works fine I get reboots and freeze when playing.

The only things that really worries me now is that the pc takes around 1 minute from turned on to bios post. Meanwhile it tries to read from the dvd several times. This started happened when I changed the Video card. May the video card bios be wrong? I tried unpluging everything but the MB and the video card and still takes around a minute.

Thanks a lot again

Thanks for the answer.

I have tried running 3dmark06 on 640x480 and then on 1440x900 and I get the same average FPS, so I guess the GPU is fine, is just the CPU bottleneck.

Also, I readed somewhere that some motherboards with nvidia chipsets causes startup delays when using an ATI video card, so that might be the reason of the other problem.

I'm gonna leave the CPU without OC (I can play Cod MW2 nicely anyway, not as good as I could, but it's ok) and try to update my motherboard/CPU/ram asap

Thanks again