My system was a e8500@4Ghz in an X38 chipset m/b (p5e) and a single 8800GT, PSU is enermax liberty 500W. Seeing the 9800GX2 going for £430 I decided the best upgrade was to add a second GT.
I swapped the motherboard for an XFX 780i board and added a second GT.
Physical install was a breeze, the XFX board supported my e8500 out of the box, unlike the P5E that required a bios flash first, even though it sported a sticker saying "compatible with new intel 45nm CPUs".
I had tried a second GT before so I knew my PSU was up to the job but at that time my CPU wasnt ([email protected]) and I was running 2 monitors.
Power readings with [email protected]:
During Post : 235w
Idle at Win XP desktop : 215w
Peak power during 3dMark06 : 362w
CPU at 4Ghz seemed to add about 30w-35w to each of these readings.
I booted into XP, installed the nforce drivers no problem and fired up 3dmark06. At 4Ghz and both GTs at stock I scored 17240. Impressive I thought.
Next on to crysis. At 1280x1024 High in XP I got 54fps, not bad. Trying at 1920x1200 I got a crash to desktop. A few reboots later and XP would continually lock up on boot.
Fine I thought, I hadnt reinstalled the o/s so Im not really suprised by this.
I installed vista ultimate 64bit with SP1, ran 3dmark06 again (16678 4ghz with GTs at stock) all is going well until I run team fortress 2 for about a 2 hour stretch. It ran fine however after exiting vista locked up, each reboot would then lock up in vista at random times.
I tried downclocking everything, still the same, eventually I threw in the towel and went back to my X38 m/b and one GT, all is well again.
Some observations:
The GTs were of different makes and speeds however the lockups occurred at the desktop and during 3d, also they occurred when the cards were clocked the same.
Under the 780i board vista seemed less responsive than the x38 chipset, I couldnt really put my finger on it, Vista experience value was the same for both.
I suspect (hope for Nvidia's sake) I had a dodgy motherboard, or it was dodgy drivers. I didnt try the board with a clean install of XP, maybe that would have sorted it.
When it was running the performance was stunning, I would advise anyone who is already running an SLI capable motherboard and a 8800GT to get another (as long as you arent using 2 monitors) and as long as you have a half decent CPU. The bang for the buck of 8800GT SLI is enormous.
I could run TF2 at 1920x1200 and 8xMSAA with no slow downs at all, during busy fire fights I could see the SLI graph showing near 80% use of the second card. Similarly 3dmark06 with a 4ghz wolfdale also used 70% of the second card for most of the time.
In XP I noticed for a few seconds during the canyon flight sequence a juddering I didnt get with one card, this was the only SLI related issue I saw though. TF2 ran very smooth on SLI and I am picky about judder and such things.
Overclocking on the 780i board was OK but it didnt correctly pick up the 9.5 multi of the e8500, the latest bios helped this but didnt resolve completely. I did however hit 4Ghz which I hit on the x38 with no problems. A superb feature of the bios was to unlink the FSB to the ram clock, so I locked my ram at 800mhz with its best timings and could then o/c the fsb independantly.
I swapped the motherboard for an XFX 780i board and added a second GT.
Physical install was a breeze, the XFX board supported my e8500 out of the box, unlike the P5E that required a bios flash first, even though it sported a sticker saying "compatible with new intel 45nm CPUs".
I had tried a second GT before so I knew my PSU was up to the job but at that time my CPU wasnt ([email protected]) and I was running 2 monitors.
Power readings with [email protected]:
During Post : 235w
Idle at Win XP desktop : 215w
Peak power during 3dMark06 : 362w
CPU at 4Ghz seemed to add about 30w-35w to each of these readings.
I booted into XP, installed the nforce drivers no problem and fired up 3dmark06. At 4Ghz and both GTs at stock I scored 17240. Impressive I thought.
Next on to crysis. At 1280x1024 High in XP I got 54fps, not bad. Trying at 1920x1200 I got a crash to desktop. A few reboots later and XP would continually lock up on boot.
Fine I thought, I hadnt reinstalled the o/s so Im not really suprised by this.
I installed vista ultimate 64bit with SP1, ran 3dmark06 again (16678 4ghz with GTs at stock) all is going well until I run team fortress 2 for about a 2 hour stretch. It ran fine however after exiting vista locked up, each reboot would then lock up in vista at random times.
I tried downclocking everything, still the same, eventually I threw in the towel and went back to my X38 m/b and one GT, all is well again.
Some observations:
The GTs were of different makes and speeds however the lockups occurred at the desktop and during 3d, also they occurred when the cards were clocked the same.
Under the 780i board vista seemed less responsive than the x38 chipset, I couldnt really put my finger on it, Vista experience value was the same for both.
I suspect (hope for Nvidia's sake) I had a dodgy motherboard, or it was dodgy drivers. I didnt try the board with a clean install of XP, maybe that would have sorted it.
When it was running the performance was stunning, I would advise anyone who is already running an SLI capable motherboard and a 8800GT to get another (as long as you arent using 2 monitors) and as long as you have a half decent CPU. The bang for the buck of 8800GT SLI is enormous.
I could run TF2 at 1920x1200 and 8xMSAA with no slow downs at all, during busy fire fights I could see the SLI graph showing near 80% use of the second card. Similarly 3dmark06 with a 4ghz wolfdale also used 70% of the second card for most of the time.
In XP I noticed for a few seconds during the canyon flight sequence a juddering I didnt get with one card, this was the only SLI related issue I saw though. TF2 ran very smooth on SLI and I am picky about judder and such things.
Overclocking on the 780i board was OK but it didnt correctly pick up the 9.5 multi of the e8500, the latest bios helped this but didnt resolve completely. I did however hit 4Ghz which I hit on the x38 with no problems. A superb feature of the bios was to unlink the FSB to the ram clock, so I locked my ram at 800mhz with its best timings and could then o/c the fsb independantly.
