Review: Low voltage modules can be fast
This article is available in German.
After Intel caused a stir for module makers by demanding lower voltages, DDR3 modules at 1.65V became the most common memory type. Now the module manufactures raised the bar by introducing 1.35V modules which do not run only at normal speeds, but are designed to please the overclocker crowd.
GSkill send us their 4GB Kit, which is rated at 1600MHz and with 7-8-7-2T latencies or if you use the SPD settings you will get 8-8-8-1T.
MSI P55-GD65 (provided by MSI)
MSI 790FX-GD70 (provided by MSI)
Intel Core i5 750 (provided by Intel)
AMD Phenom II 965 Black Edition (provided by AMD)
Scythe Kama Angle (provided by Scythe-Europe)
G.Skill 4GB Kit PC3-12800 (provided by G.Skill)
1600MHz CL8-8-8-24 CR1T 1.35V
Mushkin 6GB Kit PC3-12800 (two modules used) (provided by Mushkin)
1600MHz CL8-8-8-24 CR1T 1.65V
MSI R4850-2D1G-OC (provided by MSI)
PC Power & Cooling Silencer 500W (provided by PC Power & Cooling)
Samsung F1 1000GB (provided by Ditech)
SilenX iXtrema Pro 14dB(A) (provided by PC-Cooling.at)
Scythe DFS122512LS (provided by Scythe-Europe)
Cooler Master Stacker 831 Lite (provided by Cooler Master)
This kit consists of two modules each 2GB. For some reason G.Skill states this modules are only for LGA1156 boards. Of course that statement will not hinder us to try them out on our AMD test rig. The specified rating at 1600MHz and 7-8-7-2T timings at 1.35V is impressive. The SPD is detecting the modules with 8-8-8-1T timings, which we recommend to use. If you need it any faster, you can overclock further. G.Skill assured us, the modules will work fine with voltages up to 1.50V.
For normal operation at 1333MHz you need 1.25V to 1.30V. Our AMD board run stable with 1.248V, while the Intel board did need 1.298V. This may be a problem with the BIOS, because most boards do not detect low voltage DDR3 modules correctly, but we hope these glitches will be fixed soon.
Here is what the SPD looks like:
Let's take a look at Everest results, with C-States enabled, running at 1.35V, 1600MHz and 8-8-8-1T.
Not much difference to the Mushkin parts we reviewed recently.
Of course we tested also with AMD, because we think there is no reason why it should not work. Due to a different design the throughput is not comparable to Intel, but the controller can read or write on two channels at any given time.
When you are using overclocking modules you might want tighter timings, or higher frequency which don't always result in higher performance. We tried to go for the rated timings but with 1T. Both boards needed 1.42V which is still under the 1.50V barrier. Later BIOS-versions may result in better timings, but we were happy with our results.
With AMD even tighter timings where possible
We had no high hopes of reducing reduce power-consumption with such modules. Here are the results with the Intel P55 platform. While in idle the gap is very small, under load we were able to shave off some Watts.
The most dramatic advantage we experienced was not the lower power consumption which is nice to have, but the much lower temperatures of the modules. While even 1.65V modules can get quite hot, this kit stayed very cool during all the tests.
While we did not test for higher speeds, because we think tighter timings are much more effective, you can go either way as you see fit. With 1.42V we achieved very good results, especially on the AMD platform, so we hope G.Skill is changing the package and include the AM3 platform too.
The only drawback are boards without proper BIOS updates. Meanwhile many vendors are allowing lower memory voltages, but won't detect the modules correctly. We hope in a month or two this issue will be solved. Make sure your board supports memory voltages below 1.50V.
Compared to the standard 1.65V kits you have to pay a price-premium of about €10,-, but at €97,- this kit can not be considered expensive. Newegg is now promoting this kit, so for $104,99 you can't do anything wrong. If you don't care for ultimate speeds the same kit with CL9-9-9-24-2T is available for only €80,-/$94,99 which is a very competitive price. We like it very much and we recommend it to any Intel 1156 or AMD AM3 user.