High Speed DDR2: Buffalo and Crucial Deliver 1000+

Buffalo PC2-8000 C5: Stock Memory Performance

The current Intel platform, based on NetBurst technology, does not really allow for easily testing different memory speeds at the same CPU speed. Instead most top motherboards provide a wide range of memory ratios that match available DDR2 memory. Most end-users select the memory ratio that matches their DDR2 memory speed. For those reasons, we first test all of the stock ratios at the fastest stable timings we can achieve at the given ratio. With ratios, CPU speed remains the same at 3.46GHz in our memory test bed, and memory speed is varied by selecting different ratios.

There are some downsides to this approach. With the memory controller in the chipset, instead of part of the processor as in AM2 systems, there is a small performance penalty for speeds other than a 1:1 ratio (DDR2-533 in this case). However the penalty is in reality very small and memory scales nicely through the various speed options.

Buffalo (Stock Memory Ratios) - 2x1GB Double-Bank
CPU Ratio at 3.47 GHz	Memory Speed	Best Timings (Voltage)	Far Cry (fps)	Sandra Unbuffered	Sandra Buffered	SuperPI 2M Mod 1.5 (seconds)	HL2 Lost Coast (fps)	Quake 4 (fps)
(4:3)	400 DDR2	3-2-2-5 1.8V	62.1	INT 2816 FLT 2847	INT 5546 FLT 5523	88.6	84.8	68.7
(1:1)	533 DDR2	3-2-3-8 2.1V	63.8	INT 3489 FLT 3508	INT 6476 FLT 6476	86.3	87.2	74.3
(4:5)	667 DDR2	3-3-3-9 2.1V	64.2	INT 3980 FLT 4014	INT 6589 FLT 6626	85.2	88.7	76
(2:3)	800 DDR2	3-3-4-10 2.1V	64.6	INT 4298 FLT 4368	INT 6744 FLT 6714	84.2	89.3	75.7
(1:2)	1067 DDR2	4-4-5-14 2.3V	65.7	INT 4559 FLT 4620	INT 6829 FLT 6826	83.5	90.9	78.9
(3:5) OC 300x13	1000 DDR2* *Rated Speed	4-4-5-12 2.2V	69.9	INT 4886 FLT 4937	INT 7651 FLT 7635	75.3	99.9	86.8
Highest Mem Speed (1:2) OC 275x13	1100 DDR2	5-5-5-15 2.35V	67.3	INT 4614 FLT 4678	INT 7034 FLT 7031	81.3	92.8	81.2

The Buffalo PC2-8000 is rated at DDR2-1000, so the 1000 speed was also tested. To achieve that speed the 889 memory speed was selected at the standard 1066 FSB (266 setting quad pumped). The FSB was then overclocked to 300 (1200 FSB) resulting in a memory speed of DDR2-1000. The Buffalo FireStix clearly performed much better at DDR2-1000 than the rated timings of 5-5-5-15. Our testing found complete stability at DDR2-1000 at 4-4-5-12 timings. This is not quite as good as OCZ at 4-3-4 but it is still very fast for memory running at DDR2-1000.

The fastest possible timings with today's DDR2 are 3-2-2. If you look closely you will see the Buffalo FireStix work fine at the fastest timings that can be selected at both DDR2-400 and is nearly as fast at the stable 1:1 memory setting of DDR2-533 with 3-2-3 timings. Despite the fact that CPU multipliers cannot be dropped below 12X on the Intel platform, it is important to keep in mind that the first 5 table rows, from DDR2-400 to DDR2-1066 represent a constant CPU speed of 3.46GHz with memory running at faster speeds through ratios. 1:1 should always have the least overhead in the current Intel universe, but the DDR2 memory still scales well by speed over the full range. Memory bandwidth improves with memory speed, as does raw calculation performance. However, this does not always translate into linear gaming performance curves in Half Life 2: Lost Coast and Far Cry.

The Buffalo FireStix topped out at DDR2-1100, which is the same top speed achieved with our OCZ PC2-8000 EL. Timings were at the rated 5-5-5-15. Performance was excellent at DDR2-1100, but it was not the fastest performance found in our testing. However the FireStix matched the OCZ as being a memory that can reach the DDR2-1100 plateau.

The distinction for fastest overall performance goes to the rated DDR2 speed of 1000. At that speed the CPU is running at 13x300 or a 1200FSB, which is faster than the stock FSB of 266 or the 100 overclock from 1067 at 275 FSB. No doubt the DDR2-1000 performance was partly the result of faster memory timings and partly the result of the higher CPU frequency. 300x13 is 3.9GHz, which is certainly a good deal faster than the stock 3.46GHz.

There are other possible approaches to overclocking DDR2 memory on the Intel platform. Probably the most logical, given the memory controller resides on the Intel chipset rather than the processor, is to look at overclocking at a 1:1 ratio. For our test setup that means a DDR2-533 base setting. With the added ratio flexibility of Core 2 Duo Extreme we plan to adjust memory testing to better examine overclocking capabilities of DDR2 memory.