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

Test Results: OCZ EL PC4000 VX Gold

To be considered stable for test purposes, Quake3 benchmark, UT2003 Demo, Super PI, Aquamark 3, and Comanche 4 had to complete without incident. Any of these, especially Super PI, will crash a less-than stable memory configuration.

OCZ EL PC4000 VX Gold (DDR500) - 2x512Mb Double-Bank
CPU Ratio at 2.4GHz	Memory Speed	Memory Timings & Voltage	Quake3 fps	Sandra UNBuffered	Sandra Standard Buffered	Super PI 2M places (time in sec)	Wolfenstein - Radar - Enemy Territory fps
12x200	400 DDR (Stock V)	2-3-2-6 2.6V 1T (Stock V)	567.4	INT 2856 FLT 2998	INT 6130 FLT 6082	81	119.3
12x200	400 DDR	2-2-2-6 3.0V 1T	572.6	INT 2920 FLT 3065	INT 6150 FLT 6098	80	120.3
11x218	436 DDR	2-2-2-6 3.1V 1T	580.6	INT 3077 FLT 3253	INT 6538 FLT 6467	80	121.4
10x240	480 DDR	2-2-2-6 3.2V 1T	600.5	INT 3234 FLT 3404	INT 6804 FLT 6727	78	123.4
9x267	533 DDR	2-2-2-6 3.5V 1T	601.5	INT 3477 FLT 3679	INT 7143 FLT 7056	77	124.9
9x269 (2.42GHz)	Highest 1T Mem Speed 538 DDR	2-2-2-6 3.6V 1T	602.3	INT 3477 FLT 3683	INT 7169 FLT 7106	77	125.2
10x250 (2.5Ghz)	Rated Speed 500 DDR	2-2-2-6 3.2V 1T	612.2	INT 3364 FLT 3557	INT 7093 FLT 7009	75	128.4
10x267 (2.67GHz)	Highest CPU/MEM Performance	2-2-2-6 3.5V 1T	645.0	INT 3470 FLT 3629	INT 7554 FLT 7461	71	135.8

The top row of Performance results at 2.6V is included as a performance baseline. While VX cannot achieve 2-2-2 timings at stock voltage at DDR400, it can easily be coaxed into 2-2-2 performance at DDR400 with more voltage. With these modules, we reached an extremely stable DDR400 2-2-2-6 at 3.0V. We then maintained 2-2-2-6 timings all the way to DDR538, which required 3.6V for complete stability. The voltage requirements from 3.0 to 3.6 volts were very linear to Memory Speed.

The important results here are rows 1 to 6, where CPU speed is kept at 2.4GHZ and only the Memory Speed is varied. The performance differences that you see in that range are a result of Memory Speed only. In the case of VX, where memory timings also remain constant, the true impact of just memory speed can be seen. It is not a huge difference in real-world benchmarks, but the increase is real nonetheless.

However, speed from 400 to 533 is not the only thing that is important with OCZ VX. Please take a look at VX performance in our later performance comparisons. Look at each of these speeds, comparing VX to the best AMD TCCD and other memory that we have tested, and you will see something very interesting. VX is faster at every speed than competing memory that we have tested. This means that all 2-2-2 is not created equal, as VX is faster at every speed than the competition at 2-2-2.

OCZ EL PC4000 VX Gold (DDR500) 2x512Mb Double-Bank
CPU Ratio at 2.4GHz	Memory Speed	Memory Timings & Voltage	Everest 1.51 READ	Everest 1.51 WRITE
12x200	400 DDR (Stock V)	2-3-2-6 2.6V 1T (Stock V)	5941	2639
12x200	400 DDR	2-2-2-6 3.0V 1T	5996	2661
11x218	436 DDR	2-2-2-6 3.1V 1T	6338	2756
10x240	480 DDR	2-2-2-6 3.2V 1T	6977	2894
9x267	533 DDR	2-2-2-6 3.5V 1T	7455	3043
9x269 (2.42GHz)	Highest 1T Mem Speed 538 DDR	2-2-2-6 3.6V 1T	7466	3055
10x250 (2.5GHz)	Rated Speed 500 DDR	2-2-2-6 3.2V 1T	7236	3018
10x267 (2.67GHz)	Highest CPU/MEM Performance	2-2-2-6 3.5V 1T	7603	3160

We have looked at Aida 32 results in the past, and found them very useful in examining read/write performance and memory latency. Aida 32 is now available as Everest Home Edition and can be downloaded for free from www.lavalys.com. It is very interesting to look at the real impact of memory speed on write performance compared to memory read performance. As we raise the memory speed from 200 to 267 (DDR400 to DDR533), keeping the CPU speed constant, memory Read increases over 25% while memory Write over the same range shows just a 14% increase. That means that while all operations benefit from memory speed increases, operations more dependent on memory Read will benefit much more from memory speed boosts than those that are memory Write dependent.