[joeybuddy96]

I've already bought a Gigabyte FM2 board: GA-F2A85X-D3H.

The motherboard's memory support sheet says that 2400MHz RAM should be underclocked to 2133MHz because it runs in single channel mode when it's run at 2400MHz. I plan to upgrade to an FM2+ board soon after they are released so I can get PCIe 3.0 support. This might mean motherboards will be released that support dual channel 2400MHz, but it's not something I'm going to bother to research.

Here's the two 16GB sets I'm deciding between. The price difference is negligible.
Mushkin Blackline 2400MHz 997123R
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226426&nm_mc=KNC-GoogleAdwords&cm_mmc=KNC-GoogleAdwords-_-pla-_-Desktop+Memory-_-N82E16820226426&gclid=CMvOh6zsl7kCFUxo7AodZmgApw
I'd underclock to 2133MHz so it would run in dual channel. Would the latencies automatically change to a lower clock profile? Could I manually set them to the same as the G. Skill 2133MHz set?

G. Skill Ripjaws 2133MHz F3-2133C9D-8GXL
http://www.newegg.com/Product/Product.aspx?Item=20-231-689

The sales are limited, so I'm probably going to buy one of them in less than 22 hours if there is no forum response. Here's my spreadsheet comparing a bunch of different RAM prices:
https://docs.google.com/spreadsheet/ccc?key=0ApzIz1YSh_e7dG1kUlNvblV4cGpfMFI4SjA1ZGhMLVE&usp=sharing

 

[robbo2]

If you plan on using the graphics on the APU, then go for more bandwidth on the ram (2400) as they will just eat it up. If you're going to be using a dedicated GPU then it really doesn't matter.

 

[djsi38t]

Quote:

Originally Posted by joeybuddy96

Would the latencies automatically change to a lower clock profile? Could I manually set them to the same as the G. Skill 2133MHz set?

No.Maybe,maybe not.

 

[joeybuddy96]

I bought the Mushkin. I figure it's probably a bit more future proof, and I can adjust the latencies in the UEFI if I have to. I'll just have to test and see if running it in single-channel mode in 2400MHz versus dual-channel 2133MHz makes a difference.

 

[mindblowingj]

FM2 boards that support 2400 @ dual channel do exist already, im sending this from that exactly ( asrock extreme6 FM2 w/ gskill 2400cl9's)

 

[xd9denz]

asrock FM2A85X Extreme4 supports 2600 dual channel http://www.asrock.com/mb/AMD/FM2A85X%20Extreme4/

 

[joeybuddy96]

Oh well. I already bought the motherboard prior to starting this thread. I plan to move to an FM2+ board when the platform is released, so I'll have another chance to go with a dual channel 2400MHz or 2600MHz board then. :\ Not sure if I would have gone with an Asrock anyway, since I'm not familiar with their reputation.

 

[joeybuddy96]

I disabled XMP and AMP in the BIOS, and set the RAM multiplier to 24x, the voltage to 1.65, and the Quick timings to 11-13-13-31. The motherboard is supposed to default to single-channel mode, but CPU-Z displays it as Dual-channel mode. Without the double data rate, I'm wondering if it is actually running at 1200MHz effective. I guess I could move one stick into a non-dual channel slot, so that they are each in single-channel mode and run a benchmark in each version, then run it again with the 1.65V 9-11-11-31 2133MHz settings found on the G. Skill Ripjaws from the OP.

I ran BurnIn with the RAM, CPU temp, CPU speed, and GPU set to max load. The test failed after the RAM failed verification of data written to it on nine separate occasions. BurnIn says this is because of incorrect mathematical operations due to faulty RAM, system bus, cpu, or overheating. The CPU never got hotter than AMD's max temperature rating of 74C-the hottest it got was 67C. The drive I'm using has two bad sectors and seventeen slow sectors.

EDIT: And now I just had a shutdown. I'm thinking it might be the PSU, since the two male 4-pin connectors didn't fit the exact locked shape of the single 12V female 8-pin socket. It's an OCZ 600W. I don't know how I'd measure for voltage fails; the overclocking software with the Gigabyte board is poor, and even then I don't know what is a normal variance.

 

[EniGma1987]

Double data rate and dual channel mode are very different things, and RAM is ALWAYS running double data rate as it is part of what DDR3 is. Dual channel on the other hand can sort of be thought as similar to a RAID0 on hard drives, where you get double the speed by splitting between two channels. Not a perfect analogy, but it works well enough to get the point across. I dont see why a board would default to single channel only when it is set to a certain speed, and you can always "overclock" up to whatever speed you want. Most likely your board is running in dual channel mode though.

 

[joeybuddy96]

I'm hoping it does support dual-channel 2400. http://download.gigabyte.us/FileList/Memory/mb_memory_ga-a75m-d2h.pdf
The support list says "DDR3 2400 (Only support One DIMM Per channel)." I'm going to turn off channel interleaving and see if it helps. It might be the CPU overheating as usual, it hovers around 81C in the UEFI.

 

[mindblowingj]

Quote:

Originally Posted by joeybuddy96

I disabled XMP and AMP in the BIOS, and set the RAM multiplier to 24x, the voltage to 1.65, and the Quick timings to 11-13-13-31. The motherboard is supposed to default to single-channel mode, but CPU-Z displays it as Dual-channel mode. Without the double data rate, I'm wondering if it is actually running at 1200MHz effective. I guess I could move one stick into a non-dual channel slot, so that they are each in single-channel mode and run a benchmark in each version, then run it again with the 1.65V 9-11-11-31 2133MHz settings found on the G. Skill Ripjaws from the OP.

I ran BurnIn with the RAM, CPU temp, CPU speed, and GPU set to max load. The test failed after the RAM failed verification of data written to it on nine separate occasions. BurnIn says this is because of incorrect mathematical operations due to faulty RAM, system bus, cpu, or overheating. The CPU never got hotter than AMD's max temperature rating of 74C-the hottest it got was 67C. The drive I'm using has two bad sectors and seventeen slow sectors.

EDIT: And now I just had a shutdown. I'm thinking it might be the PSU, since the two male 4-pin connectors didn't fit the exact locked shape of the single 12V female 8-pin socket. It's an OCZ 600W. I don't know how I'd measure for voltage fails; the overclocking software with the Gigabyte board is poor, and even then I don't know what is a normal variance.

What you described there is quite normal, your timings are relatively tight, if you were running 1.65V 9-11-11-31 2133MH on 1T with the RAM you mentioned well i'd be surprised it'd be stable 24/7. That RAM is rated 11-13-13-31 (and thats most likely tested on 2T) If I were you i'd try loosing those timings... alot. Messing with channel interleaving should not help IMO. The board manufactureres say "one dim per channel" past a certain OC speed because of stbility reasons and what can be normally run, it's a generic tip. You shouldbe able to run 2 sticks at specified speed. The board does not default to single channel, it's a suggestion to plug the RAM stick into the other slot if running past a certain speed.

As EniGma1987 said, DoubleDataRate is DDR, it's just the technology you are using it's the type of RAM, this won't be turned "off" no matter what. And dual channell (I liked the analogy to explain how it works) is split up on the board phisically: usually slot 0 + 2 are a channel and slot 1 + 3 is the other one. Hence boards with 8 slots offering "quad channel" following th same principle.

 

[joeybuddy96]

@mindblowingj do you have any recommendations for what the timings should be loosened to? Those are the stock factory settings from Mushkin. With interleave channels off and the RAM sticks moved to separate channels, it finally made it through PerformanceTest. It made it through BurnIn without getting above 67C. I can try a bunch of different combinations, probably the first should be just turning interleave channels back on. Next should be moving the sticks back into dual channel slots and turning interleave back on and running them with the G. Skill settings or looser. I'm just guessing though--this is the first night I've used it with PK-1 thermal compound on the CPU and without extremely unsteady thermals. With interleave on and the sticks in dual channel slots at 2400MHz, it crashed into a DXGMMS1.sys BSOD, which may or may not have to do with temperatures or HID mouse drivers. http://answers.microsoft.com/en-us/windows/forum/windows_7-system/blue-screen-in-dxgmms1sys/db3f0576-976f-4401-8793-40f01942fb9d?page=2

 

[mindblowingj]

I'm not sure I clearly understood here, you say you were running on factory settings (which is more of a "tested maximum settings by manufacturer" imo) but also mentionned you were at 9-11-11-31 ? Making sure ive got it right: is it this RAM http://www.newegg.com/Product/Product.aspx?Item=N82E16820226426&nm_mc=KNC-GoogleAdwords&cm_mmc=KNC-GoogleAdwords-_-pla-_-Desktop+Memory-_-N82E16820226426&gclid=CMvOh6zsl7kCFUxo7AodZmgApw ? the one you liked before ? Keepinf in mind that they are high density chips (8GB compared to 4's or 2's) they shouldnt OC very much, but we can expect a little.They advertise [email protected] and usually thats 2T, if /i were trying combinations id try:
[email protected] 2T
[email protected] 1T
[email protected] 2T
[email protected] 2T
and increase untill you have something stable, then decrease one value at the time... Other factors that come to mind: Do you have a FSB, CPU-NB or HT overclock ? anyone of those would drastically change possibilities with your RAM