Assessing the impact of TLB trashing on memory hard algorhitms

[vatusasid]

I usually use 8 GPU in a system. 4x7990 + 4x other GPUs. AMD allow up to 8 GPU in the Windows sytem. So I use 8.

Most people don't like using the 7990s becuase they are pretty finicky and a pain to keep cool. I haven't had too much problem with mine after a pretty big underclock. I had one GPU go out on me while the other worked, and I had some problems with another one constantly crashing my system. I'd rather just run (5) 280Xs with no system downtime. Hey if you actually got 4x7990s running with no issues, more power to you. Your rig is like what 2100 watts?

I have 4x7990+4x7970. I undervolt and underclock them a lot. 950mv, 850/1500 MHz, the power is about 1330 and hah rate = 156 MH/s.

I have similar configurations. The hash rate is just 149 MH/s. So the DAG file size has reduced the hash rate by 3%.

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[Akarabzie]

I usually use 8 GPU in a system. 4x7990 + 4x other GPUs. AMD allow up to 8 GPU in the Windows sytem. So I use 8.

Most people don't like using the 7990s becuase they are pretty finicky and a pain to keep cool. I haven't had too much problem with mine after a pretty big underclock. I had one GPU go out on me while the other worked, and I had some problems with another one constantly crashing my system. I'd rather just run (5) 280Xs with no system downtime. Hey if you actually got 4x7990s running with no issues, more power to you. Your rig is like what 2100 watts?

I have 4x7990+4x7970. I undervolt and underclock them a lot. 950mv, 850/1500 MHz, the power is about 1330 and hah rate = 156 MH/s.

I have similar configurations. The hash rate is just 149 MH/s. So the DAG file size has reduced the hash rate by 3%.

What are you guys using to undervolt your 7990s? Just looked at mine and realized they werent actually changing from stock speeds. This may help me keep them running 24/7 since i still get the occasional crash form my 7990.

[Venon]

I undervolt my 7990 to 950 mV, and the frequency is from 820 to 880 MHz, depending on the cards.

[adaseb]

Bumping this thread...


Wondering if the RX470/RX480 will be affected by the sudden drop in hashpower when the DAG files goes to 2050MB.

Is that Dag Simulator accurate? Seems that all cards would suffer at >2GB and not just the Tahiti based cards.

[nerdralph]

Bumping this thread...


Wondering if the RX470/RX480 will be affected by the sudden drop in hashpower when the DAG files goes to 2050MB.

Is that Dag Simulator accurate? Seems that all cards would suffer at >2GB and not just the Tahiti based cards.

AMD GCN does not have a TLB to trash.  See pg. 10.
https://www.amd.com/Documents/GCN_Architecture_whitepaper.pdf

[ahsbqt]

Old thread, but R9 390 are are doing very bad these days 26mhs thanks to tlb bug.

[adaseb]

Old thread, but R9 390 are are doing very bad these days 26mhs thanks to tlb bug.

Yes with the R9 290 its even worse. I think I got 29MH/s with the stock clock settings on (947/1250) with Stilt bios. Now it gets less than 25MH/s and despite the speed decrease the power consumption more or less remains the same and hence its no longer profitable to mine with those GPUs.

Surprisingly they still hold a decent value for gamers and are selling on eBay for fair prices. Will most likely be putting mine up for auction soon. Highly doubt AMD will release a fix for the Hawaii chipsets.