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Best 16GB DDR3 kit for 1090T overclock

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May 22, 2010 8:17:43 PM

Hello, newcomer here, working on putting together my first build and I’m aiming at making a system with an AMD 1090T and 16gb memory primarily as a workstation for virtualization and creating server VMs for lab / educational purposes. I also plan on overclocking (4.0ghz+) and a bit of gaming with new title releases in the near future.

Case / Cooling: I thought a Corsair H50 with Push/Pull Exhaust setup in a HAF 932 would suffice for reaching 4.0ghz at a minimum and allow for more airflow by avoiding a gigantic heatsink (Noctua NH-D14 if I was to go high-end air).

Motherboard: I really wanted a CH IV Formula but considering all the issues with NB overheating I decided it’s best to steer clear and go with Gigabyte instead.

GIGABYTE GA-890FXA-UD5 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Memory: Due to the constraint of little variety (mostly high timings) in 4gb modules I thought a 16gb kit would be best. I’m mainly considering the following G.Skills Ripjaw series kits.

http://www.newegg.com/Product/ProductList.aspx?Submit=E...

Questions arise from having no experience with overclocking and being uncertain as to which would give the best CPU overclocking potential. From what I gather AMD favors quick timings over raw speed / bandwidth.

1. Are lower memory timings with less speed more favorable or required to overclock a Phenom II CPU? 4.0ghz+? Preferably more specific to OCing a 1090T
2. And as such, would it be a waste to go with DDR3-1333 or DDR3-1600, considering the higher price and slower timings? IE, would I be underclocking 1333 or 1600 to get stability when overclocking the CPU?
3. I'd appreciate any other memory recommendations that would be better for overclocking, but it seems choices are constrained by my need to have a large pool of memory to allocate to multiple VMs

Granted none of these models are on the QVL for the UD5, I understand that in terms of compatibility I can manually change the stock timings, speed, and voltage in order to initially get the memory and system stable.

Thanks
a b à CPUs
a b K Overclocking
May 23, 2010 6:15:44 PM

Well, as you have noticed, you not going to get a lot of feedback on the use of 16GB kits here, since 99.9% of users have no need for such a large quantity of ram.

As for your inquiry on speed vs timing, your not going to see a noticeable difference between the kits you have referenced.

Your main concern should be stability. Since I've never OCed with 4GB sticks I can't say for sure, but I would definitely try to search for users that have used and or OCed with 4GB sticks (populating all memory slots!) to get an idea of any stability problems that may be associated with this configuration.
a b à CPUs
a b K Overclocking
May 23, 2010 7:07:37 PM

There used to be a AMD AM3 ddr3 speed limitation when running dual channel memory with just one dimm per channel, never mind two. It was 1333, took me a while, but I found it. http://www.fudzilla.com/index.php?option=com_content&ta...
http://www.techpowerup.com/img/09-02-12/60a.jpg
this has been fixed supposedly ~With 4 dimms , at 4gb, your going in new uncharted territory imho.

Heres some memory tips for AM3
Memory Performance tuning – AM3 / DDR3
http://game.amd.com/us-en/content/pdf/AMD_Dragon_AM3_AM...

Quote:
Memory clock speed is tied to HT ref. clock with certain ratios. The following Memory clock modes are
available on the AMD “Dragon” AM3 DDR3 platform technology:
 DDR3-800 (400MHz) – 2:1 ratio
 DDR3-1066 (533MHz) – 8:3 ratio
 DDR3-1333 (667MHz) – 10:3 ratio
 DDR2-1600 (800MHz) – 4:1 ratio
In the case of AM3 DDR3 platform, there are two key strategies for Memory tuning:
1) utilize DDR3-1600 Memclk mode (800MHz) with CL7-7-7…CL9-9-9 timings (depending on the DIMM
specification and headroom) and minor HT ref. clock boost (below 225MHz)
2) utilize DDR3-1333 Memclk mode (667MHz) with faster CL5-5-5…CL7-7-7 timings and HT ref. clock
boost (the amount of HT ref. clock boost will depend on the DIMM OC headroom)
Option #1 is easier and works in most cases, offering the optimal amount of memory bandwidth and latency.
Option #2 could enable the absolute highest Memory performance depending on memory modules but may
require more manual tuning. Option #2 could be optimal when using DRAM modules capable of CL6-6-6
timings at DDR3-1600 speeds.
The optimal memory voltage will depend on the DIMMs. In general there are two DDR3 DIMM categories: high
voltage DIMMs that run best at 1.85…2.05V and low voltage DIMMs that prefer 1.6…1.7V.
The optimal Tras and Trc timing parameter value is calculated as follows:
Tras = Tcl + Trcd + Trp
Example: Tras should be set to 21 in case of CL7-7-7 -settings
Trc = Tras + Tcl
Example: Trc should be set to 28 in case of CL7 + Tras = 21 -settings
Enabling 2T –timing mode can improve stability with 4GB or 8GB memory configurations (but will cause a slight
performance hit).
The Memory controller of AMD Phenom and AMD Phenom II CPUs can be set to run in Ganged mode or in
Unganged mode. Ganged mode means that there is a single 128bit wide dual-channel DRAM Controller (DCT)
enabled. Unganged mode enables two 64bit wide DRAM Controllers (DCT0 and DCT1).
The recommended setting in most cases is the Unganged memory mode. Ganged mode may allow slightly
higher Memory performance tuning and performs well in single-threaded benchmarks.
Depending on the motherboard and BIOS, it may be required manually setting the timing parameters for each
DCT (in Unganged mode) when performance tuning the memory or fine tuning the timings. Some BIOS
versions apply the same timings automatically for both DCTs in an Unganged mode.
The DIMM slots furthest
May 24, 2010 3:44:27 AM

Yeah, I kind of figured overclocking with 16gb+ of memory was a rarity even in such a large community.

Only recently have I seen 16gb AMD setups, I've managed to come across a few people making 1090T setups (newegg review and other forums) utilizing full 16gb memory but unfortunately no such mention of overclocking. Prolly best to try to private message them personally to get some insights on overclocking with that much RAM.

Notty - Good find on that AMD performance tuning guide, thanks for sharing
!