We proceed with the low-level analysis of the most important characteristics of high-performance DDR2 memory modules using our RightMark Memory Analyzer. Our previous reviews in this segment were devoted to Corsair DDR2-667UL, DDR2-1000 and ADATA DDR2-800 modules. And in this article we are going to review another high-performance offer from Super Talent — a 2 GB pair of DDR2-800 modules.
Module manufacturer: Super Talent Technology Corporation
Photo of the memory module
Module Part Number
There is no DDR2 part number expansion as well as any technical documentation on this series of modules on the official web site. Product Detail page specifies that the product with Part Number T800UX2GC4 is a dual channel kit of overclocked DDR2-800 modules with the total capacity of 2 GB (2 x 1GB), 128M x 64. The modules operate in this mode with 4-3-4-8 timings. There is no information on voltages, so let's assume that the modules can operate in this mode at standard 1.8 V.
SPD chip data
Description of the general SPD standard:
Description of the specific SPD standard for DDR2:
SPD contents look rather strange. According to these data, the modules support three CAS# latencies — 5, 4, and 3. But the first (CL X) and the second (CL X-1) values correspond to the same cycle time - 3.75 ns (266.7 MHz, DDR2-533). That is the modules under review are sort of DDR2-533(!) modules — not even DDR2-667, to say nothing of DDR2-800. According to our multiple reviews of DDR2 memory modules, this irresponsible approach to programming SPD content is quite rare. Nevertheless, let's return to the examination of SPD content in Super Talent modules. The third CAS# latency (CL X-2) expectedly corresponds to higher cycle time - 5.0 ns (that is DDR2-400 mode). The main timings schemes for the first two cases (DDR2-533 mode) can be written as 5-4-4-11 (rounded) and 4-4-4-11 (rounded) correspondingly, 3-3-3-8 — for the last case (DDR2-400). You may have already noticed that such timings differ much from the official "4-3-4-8" for DDR2-800 mode.
We can also note a slightly increased minimum refresh to active/refresh command period (tRFC = 105 ns), which is more typical of "regular" rather than high-speed DDR2 modules. SPD contains the correct SPD Revision Number (1.2) and even the manufacturing date (Week 1, 2006). At the same time, Manufacturer’s JEDEC ID Code is wrong (its lettering part — 43h, 41h, 54h, 44h — can be decoded as CATD; I don't understand what it has to do with the real manufacturer) and there is no information on Part Number and Serial Number of the modules.
In the first series of tests we used the timing scheme, set in BIOS Setup by default (Memory Timings: "by SPD"). As SPD does not contain proper data for DDR2-667 and DDR2-800 modes (that's how we tested our modules), the ASUS P5WD2-E motherboard used in the testbed set timings by guess-work — 4-5-5-14 in DDR2-667 mode and 4-6-6-16 in DDR2-800 mode.
Nevertheless, according to the above results, the modules under review offer quite high performance (maximum real memory bandwidth in real tests on processors with 2MB L2 Cache is close to typical 6.8 GB/s in case of 200 MHz FSB and 9.0 GB/s in case of 266 MHz FSB). Memory access latencies are also quite low — you can see them go down when you set a higher memory frequency or a higher FSB clock (the effect is more pronounced in the latter case). In this connection the least latencies are obtained in DDR2-800 mode with 266 MHz FSB.
Timing values, except for tCL, were adjusted "on the fly" due to the built-in RMMA feature that allows to change dynamically memory settings supported by the chipset. Memory operating stability was evaluated with an auxiliary utility RightMark Memory Stability Test, included into RMMA.
Amazingly, minimum timings in DDR2-667 mode are rather average — just 4-4-3 (as usual, the last timing, tRAS, is ignored — you may reduce it down to 4 without any consequences). Note that we used the standard voltage of 1.8 V, as the manufacturer doesn't specify the necessity to use a higher voltage. This timing scheme is the best in terms of stability — these modules actually allow even "tougher" timings in DDR2-667 mode — up to 3-3-3, but it was accompanied by errors in the stability test.
It's still more amazing that in the faster DDR2-800 mode these modules were stable... with the same 4-4-3 timings (its equivalent in DDR2-667 mode is 3.3-3.3-2.5, which is a tad more conservative than the unstable 3-3-3 configuration).
As usual, faster timings allow to increase memory bandwidth and reduce latencies. But I cannot say that this effect is noticeable — for example, maximum latency reduction is demonstrated in random walks - approximately 6 ns, that is less than 5%. The increase in memory bandwidth is even less noticeable, as it does not exceed 1-2%.
Super Talent DDR2-800 memory modules, a new offer on the Russian market, are sterling representatives of the high-end class. These modules demonstrate good speed characteristics and "timing overclocking potential" — they can operate in DDR2-800 mode at nominal 1.8 V and up to 4-4-3 timings. The only drawback of the modules under review is improper quality of the SPD content that belong to some DDR2-533 modules from an unknown manufacturer, which may lead to certain problems in automatic detection of their parameters by a motherboard BIOS (theoretically it may lead to complete incompatibility). On the other hand, the fact that these modules are intended for enthusiasts who must know everything about manual configuration of various system parameters, including memory settings, probably extenuates this drawback.
Super Talent DDR2-800 Modules are kindly provided
by the master distributor of Super Talent memory modules
Dmitri Besedin (firstname.lastname@example.org)
April 14, 2006
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