New Memory Highs: Corsair and OCZ Introduce DDR550

Why Would Anyone Want DDR550?

When computer users visit some of the hard-core Enthusiast sites on the web, one of the first things that they will likely see is memory overclocking. You will see dropped multipliers and incredible FSB settings, all in the effort to raise the memory speed to the highest level possible. Skeptics always ask, why all the fuss? What do you really gain?

3.2GHz CPU Speed, Different FSB and Memory Speed

To try to answer that question, we took a close look at our 3.2ES. The unlocked CPU allows multipliers to be selected from 12 to 16, which means with DDR550 memory, we should be able to compare 3.2GHz performance at two very different settings. At a multiplier of 12 and a bus setting of 266 (DDR533), we can achieve 3.2GHz. This can also be achieved at 16x200 (DDR400) with a default 3.2 Pentium 4. So how does performance compare at the same 3.2GHz?

3.2GHz Performance - Different FSB - Corsair XMS4400
Memory Speed & Multiplier	Memory Timings & Voltage	Quake3 fps	Sandra UNBuffered	Sandra Standard Buffered	Super PI 2M places (time in sec)	Halo DX9 1024x768	Comanche 4 1024x768
400DDR 16x200	2-3-3-7 2.55V	378.5	INT 2624 FLT 2680	INT 4528 FLT 4527	108	54.9	60.25
533DDR 12x266	2.5-4-4-7 2.75V	411.9	INT 3345 FLT 3362	INT 5842 FLT 5819	102	55.2	63.25
% Change		+8.8	+26.5	+28.8	-5.6	+0.6	+5.0

At the exact same CPU speed, lowering the multiplier and increasing the bus setting and memory speed increases performance 26% to 28% in Memory. This translates to improvements in gaming performance from only 0.6% in Video-Card/CPU bound games like Halo to 8.8% in Quake 3. Keep in mind that the CPU speed is exactly the same, only the bus speed has been increased. This is what the overclockers are aiming for, at even more extreme levels than we have tested here.

In this example, there is an ongoing argument as to which really contributes to the increased performance. Some believe that the increase in the FSB to the CPU is mainly responsible for the improved performance on Intel 875/865 boards. They argue that a high FSB combined with slower memory at aggressive timings will give the exact same results. We decided to test that argument with the fastest DDR400-433 memory we have compared to this Corsair XMS 4400 at DDR533.

3.2GHz CPU Speed and Same 533 FSB, 1:1 Memory vs. 5:4 Memory

To test this claim, benchmarks were run at the same 3.2GHz CPU speed achieved with the same 12x533 multipliers. This means that the FSB was a constant 1066 in these tests. Memory was tested at DDR533 with slower timings and compared to another memory at DDR 426 (5:4) at the fastest timings available of 2-2-2-6.

3.2GHz & 1066 FSB - 1:1 Memory vs. 5:4 Memory
Memory Speed & Multiplier	Memory Timings & Voltage	Quake3 fps	Sandra UNBuffered	Sandra Standard Buffered	Super PI 2M places (time in sec)	Halo DX9 1024x768	Comanche 4 1024x768
426DDR 5:4 12x266	2-2-2-6 2.65V	412.3	INT 3061 FLT 3116	INT 5678 FLT 5695	101	55.35	63.49
533DDR 12x266	2.5-4-4-7 2.75V	411.9	INT 3345 FLT 3362	INT 5842 FLT 5819	102	55.2	63.25
% Change		0	+8.6	+2.5	-1.0	-0.3	-0.4

The results for 1:1 with slower timings versus 5:4 with fastest timings are very interesting. While synthetic memory tests like Sandra show 1:1 memory 2.5% to 8.6% faster, all the games perform essentially the same to slightly faster with the slower memory at 5:4 with faster timings. This pretty much destroys the arguments made on some sites that memory timings do not matter in high-speed memory. If Memory timings did not matter, then DDR423 would certainly perform much slower than DDR533, when in fact DDR423 is the same to faster.

In fairness, no one would argue that DDR550 at 2-2-2-6 is no faster than DDR400 at 2-2-2-6. All things being equal, faster speed will be faster. With today's memory, however, all things are not equal, and we are often forced to use slower timings as a trade-off for faster 1:1 memory speeds. Sometimes the trade-off is not worth it, and you are better off with slower memory running at 5:4 with the fastest timings possible. Do you save money with this approach? Not really, since the best DDR400 to DDR433 memory that will actually run at 2-2-2-6 timings is about as expensive as the faster memory with more relaxed timings. If you already own very fast DDR400 to 433 memory, however, 5:4 may be just as good an option as high speed memory with slower timings.

The Verdict

Faster memory running at higher speeds can clearly provide better performance, but there is no clear answer as to whether you need DDR550 memory. The market itself is very limited at present with only one or two motherboards recommended as capable of running DDR550. If you own a motherboard and CPU capable of running at DDR550 (275 setting), then DDR550 is an option. Keep in mind, however, that memory can run at slower speeds, and the performance of DDR550 in the range of DDR400 to DDR550 should be weighed in your decision.