Interesting times with HD4850 Crossfire

I have been running a HIS HD4850 for the last few weeks as an upgrade from a 8800GTS 640MB card and I thought let's go crossfire.

It worked from the outset. Just connected the card in and both bridges even though apparently you only need one, and booted up. I had 8.8 Catalyst drivers running and it detected the card but i noticed straight away i couldn't get the 2nd card to read my overclock settings or fan speeds.

After doing some digging i eventually uninstalled my drivers, Shutdown and removed the 2nd card then booted to safe mode, ran driver cleaner, rebooted and reinstalled drivers, then connected the 2nd card up again just to make sure it was working right.

After tweaking the profiles and checking by having GPU-z running I got both cards set to run the same fan speeds and overclocks.

One thing i notice is that some games like AAO, COD4 hate catalyst AI and my PC will restart itself when running them.

WoW needs the Catalyst AI or your character goes a bit see-thru, but if i over clock to say 650/990 my pc will restart itself.

I have an Antec 550W EPS12v and have ordered a Silverstone 650W ST56F to replace it in case it's a lack of power.

With just the one card running all games run fine with Catalyst AI on Advanced.

I am hoping it is the power supply not being enough.

I have the following system

Asus P5K Deluxe
[email protected] (Was at 3.5-3.6'ishGhz but backed it off in case it was the OC)
Thermaltake Big Typhoon VX CL-P0310
2x2Gig Geil PC8000@800 (901) Replacing ram today with Patriot 1066 2x2Gig DDR2 as I've never been happy with that PC8000.
2x HIS 4850 Crossfire
Antec 900 Case
1x Seagate 7200rpm 500Gig HD
1x Seagate 7200 320gig HD
1x WDC 7200rpm 200Gig IDE

Anyway I'm still testing so will post my findings here...about to install ram and try the new 8.9 Beta drivers.

After another day of mucking around with crossfire i have discovered that you don't need to install one card then install the 2nd one to get crossfire going. As long as you uninstall, do a clean with drive cleaner then install the drivers after a 2nd boot up it detects the 2nd card.
There are a few threads around on OC forums that state you need to install the main card first then do the 2nd card for it to detect.

I have it going really well now, got my new PSU and ram.

3DMark06 Score 15188
http://service.futuremark.com/compare?3dm06=8127775

Vista32bit Ultimate

3DMark Score P9116 3DMarks
CPU Score 5930
Graphics Score 11104

http://service.futuremark.com/compare?3dmv=368447

so the new psu fixed your problems in cod4?

yeah, it fixed the problem where the PC would restart after a few moments playing.

Seems to have settled a bit now and I can play all my games with no major dramas, except it has been hot temperature wise in Sydney last few days so had to up the fan speed a touch and case fans etc.

Crysis i have to play with medium settings to get any playability though. Getting around 15-30 fps depending on what's happening in the game. Benchmarks i have run come out around 25-27 fps average with 1920x1200 no aa. With 4x AA it's about 22 fps.