PCSTATS tests DDR memory on two major CPU platforms - the AMD Athlon64 and the Intel Pentium 4 - because RAM behaves differently with each processor architecture. For instance, Intel users tend to run their memory at high speeds with high latency settings, and in general that works quite well for Intel-based computers. It would be detrimental to system performance if you were to run the same DDR memory settings on an AMD Athlon64 system, since latency plays a much larger role in system performance.

Because much of our audience is made up of enthusiasts, PCSTATS also runs overclocking tests so you can get an idea on how far the memory will go.

On both Intel and AMD test PCs, we're only interested in seeing how high we can go with the memory running 1:1, as running with other dividers puts the overclocking bottleneck elsewhere, and not with the system memory. On the Pentium 4 test system we sometimes use higher latencies in our tests, as latencies are not as important. With the AMD Athlon64 test system, the DDR RAM latency must run at 2-2-2-5, or the memory's tightest possible timings, as quick access is more important to the CPU design.

Patriotic overclocking!

One thing I like about overclocking PDP Systems' memory is that they state right from the beginning what to expect. With the PDC1G3200+XBLK, they state on the label that the memory can run at 200 MHz while using the most aggressive 2-2-2-5 memory timings, while loosening things up to 3-4-4-8 should allow you to run up to 266 MHz.

Starting with our Athlon64 test system, we raised the motherboard clock speed slowly while maintaining 2-2-2-5 memory timings. At 213 MHz our system showed some signs of instability and would often crash back to desktop when running 3D applications. Raising the memory voltage to 2.8V stopped this. We easily passed 220 MHz and even 230 MHz, but seemed to hit a wall getting past 231 MHz with tight timings. Loosening the timings allowed us overclock the memory a few MHz higher, but we didn't really try too hard at this, since Athlon64 systems should always be paired with low latency memory.

With the Intel rig, things didn't start off too well. To get the memory to function properly at 200 MHz with 2-2-2-5 memory timings we had to raise the voltage to 2.6V right off the bat. After that, things went pretty smoothly and the memory overclocked nicely. Using the aggressive timings, we were limited to a maximum of 223 MHz; anything higher and we'd get a BSOD during bootup. Raising the voltage to 2.8V didn't help, so we decided to lower memory timings to 3-4-4-8 to see how fast the memory could run at higher latencies.

We were certainly not disappointed and the memory hit a very respectable 264 MHz with only 2.8V! If we tried to go past 264 MHz, the system would sometimes crash for no apparent reason. PDP specifies that the 266MHz (533MHz) speed should be accompanied by a voltage of 2.85 to 2.95V, so we were satisfied that it would reach its advertised rate.

PCStats Test System Specs: Athlon64 test system Pentium 4 test system Processor: AMD Athlon64 3200+ Intel Pentium 4 2.4C Clock Speed: 10 x 200 MHz = 2 GHz 9 x 231 MHz = 2.08 GHz 12 x 200 MHz = 2.4 GHz 12 x 264 MHz = 3.17 GHz Motherboards: Asus K8V DLX, K8T800 ABIT IC7-MAX3, i875P Videocard: Asus Radeon X800XT PE Asus Radeon X800XT PE Memory: 2x 512MB PDP Systems Patriot PDC1G3200+XBLK 2x 512MB Corsair TwinX3200XL PRO 2x 512MB OCZ PC3200 Platinum Limited Ed. 2x 512MB Corsair TwinX1024-4400C25PT 2x 512MB TwinMOS Speed Premium PC3200 Hard Drive: 40GB WD Special Ed 20GB WD HDD CDROM: MSI X48 CD-RW/DVD-ROM NEC 52x CD-ROM PowerSupply: Vantec Stealth 470W PC Power & Cooling 510W Software Setup WindowsXP Build 2600 VIA 4in1 4.55V Catalyst 4.11 WindowsXP Build 2600 Intel INF 5.02.1012 Catalyst 4.11 Benchmarks Winstone 2004 SiSoft Sandra 2004 PCMark04 3DMark2001SE X2: The Threat UT2003