990FXA-UD7 motherboard memory support

[cw4ed6]

Hi all. I have a question about memory support on the Gigabyte 990FXA-UD7 motherboard.

I have just built a pc for the first time (and to my very great surprise it actually switches on!). I have an AMD Bulldozer FX-8150 8-core processor. All of these cores appear in the BIOS at 3.6Ghz as they are supposed to. However, I also have 16GB Dual Channel (2x8GB) Corsair Vengeance DDR3 RAM, rated for a speed of 2133Mhz.

My understanding was that this motherboard supports memory speeds of up to 2000Mhz, and I thought this would automatically be scaled back from 2133 to 2000. However, on booting up the PC for the first time, the memory seems to be defaulting to 1333Mhz. I have also since been told that possibly the bulldozer processors can only support up to 1866Mhz.

I was hoping someone could tell me both what the maximum speed is available to me and more importantly, how to actually set it up?

I would appreciate any advice on the issue as quite frankly, I have no idea what I'm doing and I've been told its possible to damage the memory or processor if I start changing settings incorrectly.

Chris

[Wild Wally]

Your situation is similar to mine.  I have 2x 8GB DDR3 RAM rated at 1866 which only runs at 1333.  The memory controller on the FX chips will only run DDR3 at higher than 1600 with an overclock and extra voltage.  It also seems to have a problem with sticks larger than 4GB or having more than 2 slots occupied.  With 2x4GB you should get 1600 with an FX chip.  Larger than that will only get you 1333 at stock.  You have to tweak it to get more.

So far the best I've been able to do is 1333 with 2x8GB.  Any tweaks freeze the PC while I'm still in the BIOS screens.  The FX IMC sucks.

WW

[Vezina]

The FX IMC sucks.

WW

No ,a lot of ram on the market is made with Intel timings in mind.
AMD IMC has a different timing taste .
Specific brands tend to work better with AMD also.
Also many of this sticks on the market are over-clocked sticks ,forced to go higher than the chips where designed for , by bumping voltage.
I have found Corsair and Kingston to not work quite well on AMD ,always needing one notch back frequency wise to work.
Also some pairs may not be really matched happened to me with both Corsair and Kingston even though they sell them as matched.

The FX IMC should take 1600 and 1866 Mhz just fine.If it doesn t change the ram brand.


LE: But yes ,you should use 2 sticks and single sided ones to make sure you have them at the right frequency.If you add more sticks the stress on the IMC increases and instability may arrive.Add in the motherboard design as well and things may not go as you want.Gigabyte may have designed 2 slots of the 4 for higher speeds ,either the ones close to the CPU either the ones on the other end.

[Wild Wally]

So, which brand would you recommend?  I've never used Kingston and never had an issue with Corsair on previous AMD builds.  I am currently using another brand so I have no idea how Corsair would perform on the UD7 with an FX chip.  Interestingly enough, my phenom II's, a 970 and a 980, worked well with the same DDR3s at 1600 with no tweaks.

[Vezina]

So, which brand would you recommend?  I've never used Kingston and never had an issue with Corsair on previous AMD builds.  I am currently using another brand so I have no idea how Corsair would perform on the UD7 with an FX chip.  Interestingly enough, my phenom II's, a 970 and a 980, worked well with the same DDR3s at 1600 with no tweaks.

I see a lot of people saying G-Skill to be good also , AMD started to OEM RAM made by Patriot if i am not mistaking.The Corsair kits that i have now might be my last Corsair ram adventure.

Keep in mind the FX IMC is not like the P2 one as well.
Switch to ganged mode on a FX and then switch on ganged mode on a Phenom 2.
With P2 games would need ages to load in Ganged mode on FX a different story.

By the way have you tried Ganged mode with what you have now ?!

LE:If you Google you may find guys reaching more than 2000 Mhz on FX ,but not with this board.

[geekyadz]

Switch to ganged mode on a FX and then switch on ganged mode on a Phenom 2.
With P2 games would need ages to load in Ganged mode on FX a different story.

By the way have you tried Ganged mode with what you have now ?!

Well, according to Absic ( http://forum.giga-byte.co.uk/index.php/topic,2515.0.html ),  running in ganged mode might actually cause his memory to slow down (meaning absic couldnt get above 1333mhz on his 965 or his 1090T). Personally I have a 970, and running 1333mhz on the same memory that absic uses himself (Corsair Vengeance (low profile) @ 9-9-9-24 timings).
However, if you care to look at my CPUZ-ID screenshot (link: http://i429.photobucket.com/albums/qq14/cchaos81/private%20shyte/cpuid.png ), you will see that I have a XMP profile in the memory for achieving 1600mhz. From what I can tell, the XMP profile is for Intel boards only, but I see no real reason why it wont run at 1600mhz if the memory is at the same timings etc?

[Vezina]

I have observed personally that my Corsair (XMS) ,rated at 1333 Mhz , would run at it s rated 1333 Mhz on the FX 4100 cpu ,without strange Windows behavior ,when i switch to Ganged.
To use Unganged  i need to run at 1066 Mhz , to avoid some applications randomly not loading at start up.
And opposed to the strange slowdowns i was observing with my P2 CPU-s, when running Ganged , now with the FX it feels at least the same in responsiveness.

He should try and see what happens.
P2 IMC and FX IMC are different.
XMP profile may not work ,sometimes AMD motheboards mess all the timings up when that is selected ,seen that on my 890GPA-UD3.
XMP profile presence shows Intel compatibility not more.

[cw4ed6]

Hi all, thanks for the quick replies!

On the back of the module, it shows 10-11-10-31 and a voltage of 1.5V.

From what I understand now: the memory itself can reach 2133, the motherboard supports up to 2000 and the processor only really allows a maximum of 1866. So the maximum realistically available to me should be 1866.

Does this mean that I need to go into the BIOS and change the memory configuration from auto to manual and then where it says 1333 do I overwrite this with 1866? If doing so, do I then need to enter these other figures and the voltage anywhere (or should these only be used when running at the maximum 2133?).

I also don't understand the other option it gives me which seems to be a multiplier of some sort and has defaulted to x6.66, but it also offers x4.00, x5.33 and x8.00.

Sorry for all the questions but I've never configured this before, and information on my memory modules cannot be found anywhere on the Corsair website.

[Dark Mantis]

Hi

Firstly I want to say that whatever the modules are rated at doesn't mean they will default to that speed, just literally that they are capable of it. If you want to run at anything over the JEDEC rating then you normally have to either enable the XMP (Intel boards) or manually set the timings and voltage.

Also sometimes it can be a positive outcome to run the memory at tighter timings but less mhz (speed).

[Vezina]

Hi all, thanks for the quick replies!

On the back of the module, it shows 10-11-10-31 and a voltage of 1.5V.

From what I understand now: the memory itself can reach 2133, the motherboard supports up to 2000 and the processor only really allows a maximum of 1866. So the maximum realistically available to me should be 1866.

Does this mean that I need to go into the BIOS and change the memory configuration from auto to manual and then where it says 1333 do I overwrite this with 1866? If doing so, do I then need to enter these other figures and the voltage anywhere (or should these only be used when running at the maximum 2133?).

I also don't understand the other option it gives me which seems to be a multiplier of some sort and has defaulted to x6.66, but it also offers x4.00, x5.33 and x8.00.

Sorry for all the questions but I've never configured this before, and information on my memory modules cannot be found anywhere on the Corsair website.

Yes , switch to manual and adjust manually the frequency (via multipliers)  and timings so you get whats written on the sticks themselves.
You should be able to reach 1866 Mhz if not more ,unless they lie on the internets
When you play with the multiplier the BIOS will show you the frequency that you ve set,Just watch the BIOS info as it changes.
The BIOS may not show you all the multi values (for you to  reach what you want) , in this case you should request support from Gigabyte.

dram multiplier at  9.33 X 200(HTT) =1866Mhz
dram multi at 8 X 200=1600Mhz

Timings would be :
CL 10
Trc 11
Trp 10
Tras 31

Try the Ganged / Unganged stuff as well.
If the system stops booting after modifieng timings reset BIOS and try again until you get them right.
If it boots to windows run Memtest for 20 passes or so.

[cw4ed6]

Thanks very much for all the information guys! I will have a stab at it and see how far I get. If nothing else I can at least say that building the PC has been a significant learning experience! 

Thanks again!

Chris

[furball zen]

Im having the same issue with my UD5. In the BIOS it recognizes my Corsair Vengeance LP as 1600 but anything over 1333 results in a 'crash' which just seems to be limited to a warning message about a boot failure after a reboot. I find it hard to believe its the chip not the mobo. Also i cant get any OC on the proc or the same thing happens.

Forgot to say its an FX-6100.

[furball zen]

Seriously? No suggestions?