Gigabyte 990FXA-UD7 (Or any Gigabyte motherboard) Bulldozer Core Disabling

[I.M.O.G.]

On the Crosshair V Formula, I can disable one core at a time if I have one of a few specific bios versions designed for that purpose.

I'm currently using a Gigabyte motherboard for the first time with Bulldozer. In the bios, I only have the options to disable core1&2, core 3&4, core5&6, and core7&8. I cannot disable cores 2, 4, 6, and 8. (Asus is the same on their stock bios)

Is there a bios out there for Gigabyte that enables individual core disabling?

I'd like to disable the even number cores to improve benchmark efficiency, as I'm trying to win a contest that doesn't use more than 4 cores at a time. By disabling half of each bulldozer module, benchmark scores improve as then its one core per one FPU.

 

[I.M.O.G.]

The current BIOS on my board is 10/7/2011 by the way. I looked on Gigabyte's site, and there isn't one listed with that date, however it might be the same as the one on their site listed as 10/14/2011. I'm currently updating bios to F7 (12/2/2011) and F8f (2/13/2012) to see if this functionality exists.

If anyone has an answer about unofficial bioses or anything else you've heard, input appreciated. I will post back with my results.

 

[Aldakoopa]

When an FX-6100 goes into turbo mode, if it works the same as the other turbo modes on the FX series, then it disables half the cores... which would mean it would have 2 modules enabled, but one of them running both cores, and the other running only one, so in theory it should be possible... On a side note, why didn't they just make all the turbo modes disable one core in each active module instead of disabling whole modules? That would make more sense and probably give better performance... =/

 

[I.M.O.G.]

Interesting notes about turbo mode. I always disable turbo mode so its running exactly what I set, and I haven't ever heard that before. Good info.

I just updated to the F8f bios, and it doesn't let me disable individual cores... However, much to my delight, it has a function called "one core per compute unit". This doesn't allow you to select cores, but it disables one core per compute unit, which is pretty much what I wanted to do.

It would still be better if I could disable all but core 1 and core 3. For single threaded benchmarking, you get better scores with only one core per compute unit, and with 2 cores enabled - one for the OS and stuff, the other for the benchmark you are running.

 

[Aldakoopa]

I just read on another site of 2 or 3 people being able to disable individual cores in the BIOS of their Crosshair V's, they didn't mention that they were formulas though (but I don't imagine that would make a difference in this situation) As far as I could tell they were using the stock BIOSes. http://www.overclock.net/t/1175303/hey-look-a-bulldozer-thread

 

[I.M.O.G.]

Ya, the only crosshair V currently is the formula, so thats what they'd be running. I'm not sure what their latest bios does (I've ran their latest bios, but I haven't paid attention to its core disabling - anytime I disable cores on the CVF I use a specific bios for what I'm doing), but last I checked it wasn't per CU disabling, only core. On asus boards though, the special bios to disable cores is pretty popular as thats what was used to set some records and there are always modified bioses available for the Asus stuff - their users are used to grabbing special bios files from forums.

 

[Aldakoopa]

Ya, the only crosshair V currently is the formula, so thats what they'd be running. I'm not sure what their latest bios does (I've ran their latest bios, but I haven't paid attention to its core disabling - anytime I disable cores on the CVF I use a specific bios for what I'm doing), but last I checked it wasn't per CU disabling, only core. On asus boards though, the special bios to disable cores is pretty popular as thats what was used to set some records and there are always modified bioses available for the Asus stuff - their users are used to grabbing special bios files from forums.

I didn't know that about the Crosshair V's, I assumed there was the Crosshair V, and then there was the Crosshair V Formula. I haven't actually looked at any Gigabyte boards at all since building my computer, and even then I didn't check out the Crosshair. I was assuming the "Formula" was an extra name for a slightly better model, for example there was the Pontiac "Firebird" and then there was the slightly better "Firebird Formula". Other than that, I have no idea about individual core disabling. My BIOS groups them together like you stated yours did. I don't know why the people who posted on that forum were saying they could disable individual cores, unless they were talking about the "one core per compute unit" setting you mentioned.

Can you not disable two of the modules, and set the one core per compute unit and get two cores like you want?

 

[I.M.O.G.]

Looks like under loads I'm not getting a stable frequency. It fluctuates.

I have LLC set to extreme, C1E set to disabled, C6 set disabled, Kool & Quiet set disabled.

Any other tricks I'm missing here?

As for the crosshair, usually they come out with an extreme version in addition to the formula. So far we've only got the CVF however, and no extreme version - not sure if its coming or not.

EDIT: Looks like I'm getting a stable frequency now. Just rebooted and saved bios settings again. It seems once I make any change in easytune software, throttling takes effect again. Easytune SUCKS.

 

[ssjwizard]

The gigabyte core disable is not quite as advanced. You have two options, either 1 core per unit giving you 4 cores active OR disable whole modules, but you cant do both.

 

[I.M.O.G.]

Ya, not a very high demand feature, so I understand. I guess if you buy Asus boards, you pay well for the small details - core unlocking and software are 2 notable advantages.

I only would use them for benchmarking though, I can't think of any worthwhile use for daily usage. Some would like good software overclocking for gaming though, and easytune needs improvement to serve that group well IMO.

I also can't see any way to set more than 1.9V on the CPU. Not a feature everyone is looking for, but its pretty critical to what I'm trying to do. I'm only getting 1.88V in windows under load, and I am shooting for 1.98V. 1.88V will do, but it means a couple hundred MHz lower on core frequency.

 

[Aldakoopa]

The gigabyte core disable is not quite as advanced. You have two options, either 1 core per unit giving you 4 cores active OR disable whole modules, but you cant do both.

I see. Stupid details.

 

[I.M.O.G.]

Any word on the 1.9V vcore limit? This is the first time I've powered on this board, and it looks like the only way I can change voltage is via the offset... Using its max setting gives me 1.9V in bios. If I could get to 2.0V that would be awesome.

 

[Apht3rThawt]

I run a Gigabyte 890FX with bios version F5. The core enable/disable allows individual core control. Here is pic. Also 1055t with 2 cores active for high oc.

 

[I.M.O.G.]

Thanks. That looks like a thuban. I found phenomIIs had individual core control, but bulldozer was different.

 

[Apht3rThawt]

Thanks. That looks like a thuban. I found phenomIIs had individual core control, but bulldozer was different.

I thought BDs had modules, not cores as such; would be hard to control cores if they are part of modules. That may be why no individual core option. And you did say "any Gigabyte" in the thread header.

 

[I.M.O.G.]

Ya, I should have specified Bulldozer CPUs.

You can disable individual cores (modules) within bulldozer, it just depends on the BIOS support provided by the motherboard manufacturer. You can only do every other core on gigabyte (core 0, 2, 4, 6) with bulldozer. On phenom you can control each core independently on Gigabyte, but thats true of any motherboard vendor.

I fixed the title as it should have been more clear from the start, my bad.

 

[Bobnova]

AMD specifically doesn't recommend doing one core/module, so I'm not especially surprised GBT hasn't done much with it. It'd be nice if they did though.

It might be worth emailing the top mobo PR people there (I can give you their email addresses, if you don't have 'em), pointing to your BD records, and requesting a BIOS with that functionality.