Kingston Launches Low-Latency DDR3

Bandwidth and Memory Scaling

AMD includes the memory controller on their processors, but Intel continues to make the memory controller a part of the motherboard chipset. While the on-chip memory controller is theoretically superior, Intel manages to continue to improve memory bandwidth on their new chipsets. You have already seen in DDR3 vs. DDR2 and Intel P35 Memory Performance: A Closer Look that the new P35 improves memory bandwidth 16% to 18% compared to the same speed and memory timings on P965.

Kingston KHX11000D3LLK2 is the first to offer lower latency in DDR3 and this should further improve memory bandwidth. We compared Standard or Buffered bandwidth on the P965 running DDR2, the new P35 running DDR2, and the new P35 running Kingston DDR3-1375.

Standard (Buffered) Sandra XI.SP2 Memory Bandwidth - 2.66GHz
Memory	800	1066	1333	1520 (380x7)
Kingston DDR3-1333 KHX11000D3LLK2	6341 5-4-3-10 1.75V	6736 6-5-5-12 1.7V	6928 7-7-6-15 1.7V	7329 8-8-8-22 1.8V
Corsair DDR3-1066 CM3X1024-1066C7	6156 6-6-6-15 1.5V	6613 7-7-7-20 1.5V	6757 9-9-9-25 1.5V	-
DDR2 - P35 Corsair Dominator	6456 3-3-3-9 2.25V	6811 4-4-3-11 2.3V	-	-
DDR2 - P965 (10x266) Corsair Dominator	5531 3-3-3-9 2.25V	5782 4-4-3-11 2.3V	-	-

At DDR3-800 the Kingston manages stable 5-4-3-10 timings at 1.75V. Based on current motherboards and JEDEC standards the fastest available DDR3 timings are 5-3-3, so the Kingston DDR3-1375 is very close to the theoretical limit at DDR3-800. With the improved timings DDR3 is about 3% faster than DDR3 at 6-6-6 timings. Fast DDR2 on the P35 supporting DDR2 is the widest buffered bandwidth, but the difference between P35 DDR2 3-3-3 and P35 DDR3 5-4-3 is less than 2%. All P35 results, even the lower 6-6-6 timings, exhibit higher bandwidth than P965 at DDR2 3-3-3.

At both 800 and 1066, Kingston DDR3-1375 bandwidth is very close to the bandwidth of fast DDR2 on the P35. Again, all P35 results, even slower DDR3, are faster than P965 with fast DDR2 memory. At 1333 the 7-7-6-15 timings improve bandwidth by around 2.5%, and using lower latency allows the Kingston to run as fast as DDR3-1520 at 8-8-8-22 timings. However, the best bandwidth was achieved at faster timings and slightly slower speed. As shown above, the Kingston managed 1500 speed at 7-7-7-15 timings where standard buffered bandwidth is almost 7500 MB/s.

We also test memory with buffering schemes like MMX, SSE, SSE2, SSE3, etc, turned off. While these features do provide apparent improved bandwidth, the unbuffered bandwidth tends to correlate better with actual gaming and application performance. Unbuffered performance does not always follow the patterns of buffered memory performance.

Unbuffered Sandra XI.SP2 Memory Bandwidth - 2.66GHz
Memory	800	1066	1333	1520 (380x7)
Kingston DDR3-1333 KHX11000D3LLK2	4411 5-4-3-10 1.75V	4761 6-5-5-12 1.7V	4936 7-7-6-15 1.7V	5172 8-8-8-22 1.8V
Corsair DDR3-1066 CM3X1024-1066C7	4098 6-6-6-15 1.5V	4547 7-7-7-20 1.5V	4702 9-9-9-25 1.5V	-
DDR2 - P35 Corsair Dominator	4536 3-3-3-9 2.25V	4926 4-4-3-11 2.3V	-	-
DDR2 - P965 (10x266) Corsair Dominator	4226 3-3-3-9 2.25V	4608 4-4-3-11 2.3V	-	-

Unbuffered results show the same basic pattern as buffered results in this case, although the domination of P35 in bandwidth performance is not as pervasive. At 800 and 1066 speeds, best bandwidth is with fast DDR2 on the P35 chipset, next is this Kingston DDR3-1375, then Fast DDR2 on P965, and last is slower DDR3. Unbuffered bandwidth is a good mirror of real-world performance, and this is what we expect in gaming tests. It is interesting that the lower latency Kingston has now passed DDR2 on the P965 and is nearly the equal in unbuffered bandwidth to fast DDR2 on P35.

Of course DDR2 could not do the 1333 speed, so the higher speeds of 1333 and 1500+ are the domain of DDR3 and here the Kingston memory shows its true capabilities. Lower latency DDR3 appears to be able to close any gaps that might exist in the overlap speeds of 800 and 1066.