How much RAM required per 7970?

[MrBilling]

So how much RAM is required to run each 7970?  I have heard half the RAM to 7970, so 1.5GB per 7970.  But I have also heard the RAM must match the amount of memory per 7970, so 3Gb per 7970.


Anyone?

[whitetoo]

I'm running 3x 7970 on 8GB no problem.

[kendog77]

Setup:
Linux Ubuntu 12.04
cgminer 3.0.0 mining litecoin
4x 7950s at over 600k per card (2.433 Mh/s system average)

Memory usage appears to be under 2 gigs.

~$ free -m
             total       used       free     shared    buffers     cached
Mem:          3903       1660       2242          0        118        617
-/+ buffers/cache:        924       2979
Swap:         4042          0       4042

[BTCClicks]

You don't need much memory for mining bitcoins.

[Wilderness]

I have 4 x 7970 3 gb mining LTC with 8 GB ram if you're wondering about LTC mining
runs BTC with just 2gb

[kevinmyers80]

I believe that 2 gb is more than enough, I have 1 gb and a 7970 ... and never any trouble ...

[bcpokey]

I'm honestly a little confuzzled by all this ram and scrypt stuff.

I have 4GB on a machine, and running 3x7970s with CGMiner, they absolutely refuse to run with a thread concurrency above 18k. I looked back over the posts and ck says that he thinks it's a ram issue, and no other solutions have been offered. The cards run at lower concurrency, but at much lower hashes than I would like (something like 575KH/sec for a 7970 is poor) because of the subpar settings they are running under. They didn't have this issue when there was only 1 7970.

So be aware that more cards may yield more problems.

[kendog77]

7970s are very finicky beasts. I have a windows 8 machine with 2 7970s and 8 gigs of ram, and can't even get cgminer to start most of the time after tweaking settings.

I have one config that does work and yields ~630k per card mining litecoin, so I'm sticking with that for now, but it's frustrating because I know I should be able to get more out of these cards.

I don't think it has anything to do with the amount of RAM in the system because 8 gigs should be plenty.

[Wilderness]

kendog these are the settings I use for a 4 x 7970 rig 8gb ram and get 750mhash for mining LTC

:loop
cgminer.exe --scrypt -o stratum+tcp://eu.wemineltc.com:3333 -u username.1 -p password --shaders 2048 --lookup-gap 2 --thread-concurrency 8192 -I 13 -g 2 -w 256 --gpu-engine 1100 --gpu-memclock 1500 --auto-fan
timeout /T 10
goto loop

[GuiltySpark343]

I have 3x 7970 running CGMiner 3.1.0 off of Win7 x64, Catalyst 13.1

I get about 500 kh/s (per card) using:
--scrypt --shaders 2048 --lookup-gap 2 --thread-concurrency 8192 -I 13 --gpu-engine 1000 --gpu-memclock 1675

When I try the settings above by Wilderness, I drop to about 380 kh/s (per card). Not sure why my cards don't do well with those settings. Very odd.

[notaek]

Across two 7970's, I am using 2.8 gigs.

1,398,780k on one
1,405,892k on the other

[Kennji]

My 7970 is on a rig with 1gb ram.  Running fine.

[MashRinx]

My 7970 is on a rig with 1gb ram.  Running fine.

3 x 7970 in rigs with 2 GB RAM running fine, BTC or LTC mining