OCZ VX Memory + DFI nForce4 = DDR533 at 2-2-2

Performance Test Configuration

The OCZ VX DDR500 was tested with the DFI LANParty nF4 SLI-DR Athlon 64 Socket 939 motherboard. The new DFI nForce4 SLI and Ultra are the only current production boards that support the voltages required for top VX performance. An OCZ DDR Booster can be used with motherboards without support for high memory voltages. Other components remain the same as used in the memory setup in Athlon 64 Memory: Rewriting the Rules .

All other memory tests were run earlier on the MSI K8N Neo2, based on the nForce 3 Ultra. We have already shown performance of the nF3 and nF4 to be virtually identical in our launch reviews of the nForce4 chipset. Similarly AGP and PCIe performance has been shown to be virtually the same using the same video card (6800 Ultra AGP vs. 6800 Ultra PCIe. For these reasons we did not retest earlier memory on the DFI. However, we were concerned about the potential performance difference in 61.77 video drivers compared to 71.80, so we ran a quick set of comparisons. 71.80 drivers were slightly faster in game benchmarks than 71.80 and slightly slower than 61.77 in memory bandwidth tests. However, the differences were small enough that we were confident the results were not seriously distorted by using the 71.80 drivers.

The A64 test bed for testing the OCZ VX and the standard MSI test bed both include components that have been proven in Socket 939 Athlon 64 benchmarking, such as the Socket 939 FX53 (same specifications as current 4000+), and the OCZ Power Stream 520 Power Supply. Since the Athlon 64 tests represent a new series of DDR testing, we have chosen the current generation nVidia 6800 Ultra video card for benchmarking. We have found the 6800 Ultra to be a particularly good performance match to nVidia motherboards.

All other basic test conditions attempted to mirror those used in our earlier Intel memory reviews. However, test results are not directly comparable to tests performed on the Intel test bed.

AMD nForce4 Performance Test Configuration
Processor(s):	AMD FX53 Athlon 64 (2.4GHz, Socket 939, 1 MB cache, Dual Channel, 1000HT)
RAM:	OCZ EL PC4000 VX Gold (DS) 2X512MB Corsair TwinX1024-4400C25 (DS) 2X512MB G. Skill TCCD (DS) 2X512MB PQI 3200 Turbo (DS) 2X512MB Crucial Ballistix (DS) 2X512MB Geil PC3200 Ultra X (DS) 2X512MB OCZ PC3200 Platinum Rev 2 (DS) 2X512MB OCZ PC3700 Gold Rev 3 (DS) 2X512MB
Hard Drives:	Seagate 120GB PATA (IDE) 7200RPM 8MB Cache
PCI/AGP Speed:	Fixed at 33/66
Video Card(s):	nVidia 6800 Ultra 256MB, 256MB aperture, 1024x768x32
Video Drivers:	nVidia Forceware 71.80 nVidia Forceware 61.77
Power Supply:	OCZ Power Stream 520W
Operating System(s):	Windows XP Professional SP1
Motherboards:	DFI LANParty nF4 SLI-DR MSI K8N Neo2 Platinum (nForce3)

With nForce3 motherboards, we achieved the fastest performance on AMD Athlon 64 chipsets (nForce3, VIA K8T800 PRO) at Cycle Time or tRAS of 10. However, as we saw in the recent nForce4 SLI roundup, the nForce4 appears to behave a bit differently with memory. In the SLI roundup, we found a tRAS of 7 to be ideal for memory based on Samsung TCCD chips. Therefore, we ran a complete set of Memtest86 benchmarks with only tRAS varied to determine the best tRAS setting for OCZ VX.

Memtest86 Bandwidth DFI nForce4, Athlon64 4000+, OCZ VX
2 tRAS	2572
3 tRAS	2572
4 tRAS	2572
5 tRAS	2640
6 tRAS	2640
7 tRAS	2640
8 tRAS	2505
9 tRAS	2505
10 tRAS	2505
11 tRAS	2441
12 tRAS	2383

These tests are particularly easy to do with the DFI nF4 boards, since memtest86 is built into the BIOS. To boot memtest86, you only have to enable it in BIOS and the system will boot directly into memtest86. This makes it very easy to test various memory timings, but memtest86 should be disabled in BIOS when you are ready to boot into the system.

The best memory bandwidth with VX and the 4000+ was achieved in the tRAS 5 to tRAS 7 range. Therefore, all VX testing was done with a tRAS setting of 6.

Test Settings

All AMD Athlon 64 processors are unlocked downward, and the FX CPUs are unlocked up and down. This feature allows a different approach to memory testing, which truly measures performance differences in memory speed alone. All tests were run with CPU speed as close to the specified 2.4GHz of the 4000+/FX53 as possible, with CPU speed/Memory Speed increased at lower multipliers to achieve 2.4Ghz. This approach allows the true measurement of the impact of higher memory speed and timings on performance, since CPU speed is fixed, removing CPU speed as a factor in memory performance.

The following settings were tested with the OCZ EL PC4000 VX Gold on the DFI nF4 test bed:

1. 2.4GHz at 12x200 (DDR400) - the highest stock memory speed supported on K8T800-Pro/nF3-4/SiS755-FX motherboards.
2. 2.4GHz at 11x218 (DDR436) - a ratio near the standard DDR433 speed
3. 2.4GHz at 10x240 (DDR480) - a ratio near the standard rating of DDR466
4. 2.4GHz at 9x267 (DDR533) - a standard memory speed used in testing other high-speed memory
5. Highest Memory Speed - the highest memory speed that we could achieve regardless of the multiplier. This setting was achieved at a 1T command rate with the VX, so this is also the result that produces the best memory performance.

Command Rate is not normally a factor in Intel 478 tests, but it is a major concern in Athlon 64 performance. A Command Rate of 1T is considerably faster on Athlon 64 than a 2T Command Rate. For this reason, we had added the Command Rate to the timings and voltage reported for each memory speed setting.

We ran our standard suite of memory performance benchmarks - Quake 3, Return to Castle Wolfenstein-Enemy Territory-Radar, Super Pi 2M, and Sandra 2004 Standard and UnBuffered. Since the results for Athlon 64 tests are new, we are now including Sandra Buffered (Standard) test results and Sandra UnBuffered test results. RTCW Enemy Territory has also been added as a standard memory benchmark.