Just got a 7770, how to downclock video memory in windows?

[ThaSpacePope]

I've been a casual windows bitcoin miner since last june, mostly using guiminer and Poclbm at about 1.2Ghash with mostly 6000 series cards, but this is my first 7000 series card.

So far I've only been able to get the MSI 7770 to about 1075 getting 203Mhash with diablominer.

But I can't find a program that will underclock my memory. This 7770 is using a ton of wattage at 925mhz memory (1075-150 = 925mhz), about 88W. Anyone have a way to downclock? I've tried afterburner, barelyclocked sapphire trixx and cgminer.exe --gpu-memclock 300 commands all to absolutely no avail.

Info:

Windows 7
12.6 drivers
amd 12.7 sdk

I've also tried the 12.7 beta drivers too. Memory does not budge. Is this a known issue with 7000 series cards or is there a solution i'm not finding? With all my 5000 & 6000 series cards afterburner or barelyclocked or trixx all seemed to work with various success. Not so with this 7770.

Any help MUCH appreciated!

[ThaSpacePope]

Well I finally found that going back to 12.3 fixed it or "allowed" me to use a combo of afterburner & barely clocked to sneak in the memory settings to 300mhz.

[ThaSpacePope]

Wow this card is very strange. Last night before going to bed wattage was 107W for entire system. This morning wattage was 96W. I know these cards do something called a long idle but when checking the temp history it had stayed at 70C. Looking at the Mhash, average was unchanged @ about 205mhash for 1100mhz core.

I guess shutting the attached screen off on these cards drops their wattage down a lot? With the long idle this puts this 7770 at about 71W total for 202mhash. Pretty good!

[crazyates]

Long Idle is only when the card is doing nothing. Long Idle has no affect on mining.

Are you saying your system pull was 107W idle, or while mining? My computer's idle can vary anywhere from 86 to 96 (idle meaning not mining), so a 10W difference is hard to be tracked down or attributed to the GPU.

Also, I thought those 7xxx cards couldn't go to 300MHz mem? I thought they had to be within a certain range of the Core speed? Can you verify with GPU-Z that you are actually mining at 1100,300?

[ThaSpacePope]

Long Idle is only when the card is doing nothing. Long Idle has no affect on mining.

Are you saying your system pull was 107W idle, or while mining? My computer's idle can vary anywhere from 86 to 96 (idle meaning not mining), so a 10W difference is hard to be tracked down or attributed to the GPU.

Also, I thought those 7xxx cards couldn't go to 300MHz mem? I thought they had to be within a certain range of the Core speed? Can you verify with GPU-Z that you are actually mining at 1100,300?

Thats what I thought. However, I don't get it. I verified that the HD was still spinning but indeed the watts used was down to 96 from 106. This is total system wattage. The system is just an intel g630 / 8GB / 2TB HD. Without the video card in the system and using the IGP it only uses 25W total. So this 7770 uses somewhere between 71 and 81W while hashing 205MH/sec @ 1100 / 300. Unfortunately games cannot be played @ 1100 but hashing seems ok.

Yes I can verify its @ 1100 / 300. I had to drop back to 12.3 drivers with the 2.7 sdk. I'm not sure if 2.6sdk is faster, haven't tested it. 12.6 drivers did NOT allow me to downclock vid memory below 925. 12.3 does. Hope this helps someone.

[scifimike12]

Also, I thought those 7xxx cards couldn't go to 300MHz mem? I thought they had to be within a certain range of the Core speed? Can you verify with GPU-Z that you are actually mining at 1100,300?

They can do below 300 just fine.  All of mine are at 170MHz and have been doing that for quite a while.  I am using Catalyst 12.7 beta by the way. 

@ThaSpacePope, what PSU are you using?  Remember you have to factor in efficiency when you calculate what you're drawing from the wall.  My 7970 undervolted and clocked to 1000/170 draws 230W with a Sempron 140 and SSD.  The PSU I'm using is an Antec HCG-400M.  It's 80+ Bronze so if I factor that it's around 83% efficient at that load that I should be drawing 191W.  Then subtract the CPU + board + SSD + case fans which add around 45W.  So the card itself is consuming 146W.

[QiVX]

I'm not sure about this, but in Windows I use any OC tool to set my voltages, then I use CGMiner to set my clocks.

Can you just try CGminer, press G for GPU Mangement, select GPU via ID (look at hash rates above to see which one is the card), then press M for Memory clock, and set 300.

[crazyates]

I just got a 7770 in the mail today (the Gigabyte factory OC one @1100MHz. It's on Newegg for $90 right now), so I tried it out. I'm on Win7x64, with 12.6 (with included SDK). I"m running CGMiner 2.5.0, but CGMiner can't lower the mem speed below 150MHz under the core speed. So at 1100MHz, I can't go lower than 950. That's what the "--gpu-memdiff -150" option is for.

However, while I was mining, I fired up AB 2.2.1. I lowered the mem bar all the way to the left, which was about 650Mhz, and hit apply, and no issues. I closed AB, and opened it again, which keeps the mem at the same speed, but resets the bar to the middle, which lets you go lower. I did it again, this time to 310MHz. I did it a third time, to round it off right at 300Mhz. This is confirmed in CGMiner, GPU-z, and my Kill-A-Watt as lowering the memory to 300Mhz (and lowering power) on the newest drivers.

Here are my Kill-A-Watt numbers:

Idle with no card: 83W
Idle with card: 89W
Mining on card: 157W
Mining with lower memory: 149W

This makes 66W for the card alone. This bumps it up from 2.7MHs/w to 3.0MHs/w.

I'm currently sitting at 68C @ 37% fan.