Overclocking The Low-cost System, Continued
At 470 MHz, the system seemed stable, and able to run Orthos without errors or crashing. Maybe we could have taken it further, but with a high load temperature and a 450 watt power supply, this was as high as we were comfortable running this rig on a long-term basis.
Satisfied with our overclock, we turned our attention to the Geforce 8800 GTS 320 MB. We used AtiTool to push the 8800 GTS past the stock limits, and we were greatly rewarded with a core clock speed of 610 MHz and a memory clock speed of 950 MHz. This is fantastic, considering the reference 8800 GTS speed of 500 MHz core / 800 MHz clock, and will really help this system compete with the 8800 GTX in the gaming arena. The 8800 GTS appeared rock-stable at this overclocked speed in AtiTool's artifact tester.
With the overclock locked in, we ran the benchmarks. We experienced two problems: instability in one of the SPECviewperf benchmarks, and some anomalous results in the game benchmarks. Apparently our stable overclock wasn't so stable; even though Orthos proved the CPU could run at the overclock we chose, and AtiTool's stress tester proved the graphics card could run at that setting, it seemed that things were getting a little unstable when both the CPU and graphics card were stressed. Perhaps the PSU was struggling to provide fuel to both CPU and graphics card when they were drawing at the same time...
In any case, lowering the FSB to 460 MHz and increasing the north bridge voltage got us a final stable overclock of 3680 MHz, which worked for all benchmarks and tests without any problems. Our final numbers were a little smaller, but we still managed an over 1 GHz overclock with our mighty 450 watt power supply!
On a final note: if you're planning to buy a system for overclocking duty, don't skimp on the power supply. We chose the Fortron PSU because it works well and kept us under our $1,000 budget, but if overclocking is your goal you should consider something meatier.
| Low-Cost Overclocked Component Settings | |
|---|---|
| Processor | Intel Core Duo e6750, 2.67 GHz, 1333 FSB, 4 MB Cache |
| Final Overclock | 3.68 GHz: 8x 460 MHz FSB, 1.475 Volts Core |
| Motherboard | ASUS P5K, BIOS: 0507 |
| Final Overclock | Northbridge @ 1.45V |
| RAM | Wintec Ampo PC2-6400, 2x 1024 MB, CAS 5.0-5-5-16 |
| Final Overclock | 920 MHz Data Rate, CAS 4.0-4-4-16, 2.1 Volts |
| Graphics Card | EVGA GeForce 8800 GTS 320 MB, 500 MHz GPU, 1600 MHz RAM |
| Final Overclock | 610 MHz GPU, 1900 MHz RAM |
Now that you know how we did it, let's look at the results.
