Share your experience on RAM/GPU ratio

[wijnand1]

I have heard numerous stories about the amount of RAM needed for mining. When building my own rig I encountered problems when running 1 290x on 4gb RAM (Windows 7), an error showed up in cgminer. After pacing another 4gb the error disappeared.

Having this error is searched for info and saw many different views, varying from 2GB/GPU needed to people running 5x 290x on 4 GB of RAM.

I thought it might be caused by the operating systems that is used?

Please share your experience and expertise.

[matt4054]

I have come to the conclusion that the amount of system RAM required heavily depends on

• Thread concurrency
• Number of GPUs

I have also come to the conclusion that the system RAM is only required to create the kernel code that cgminer then transfer to the GPUs. In other words, once the kernels are built, you no longer need the system RAM *until* you change whatever parameter in cgminer that affects the kernel, then cgminer will need the RAM again to re-build the kernel.

I may be totally wrong though, asked and still looking for certainty about cgminer and system RAM requirements. Given that CK has now totally removed GPU support from cgminer, I didn't ask him directly (as doing so might be perceived uninformed/trollish)

[wijnand1]

I agree the number of GPU's will most likely affect the use of RAM. However I know people running 5 290x on same mobo, psu and config using only 4GB, where as mine wouldn't work with 1 card on 4 GB. The only thing i could come up with was the us of another OS. Looking into windows reveals that 2gb of memory is reserved for 1 GPU

Might it be an option to contact the dev of sgminer since this is being maintained and updated for GPU mining and is essientially the same as cgminer?

[crazyates]

I have come to the conclusion that the amount of system RAM required heavily depends on

• Thread concurrency
• Number of GPUs

I have also come to the conclusion that the system RAM is only required to create the kernel code that cgminer then transfer to the GPUs. In other words, once the kernels are built, you no longer need the system RAM *until* you change whatever parameter in cgminer that affects the kernel, then cgminer will need the RAM again to re-build the kernel.

I may be totally wrong though, asked and still looking for certainty about cgminer and system RAM requirements. Given that CK has now totally removed GPU support from cgminer, I didn't ask him directly (as doing so might be perceived uninformed/trollish)

You are correct, to an extent. It was my impression that the system memory was only used to build the initial kernel, which does get larger the higher your TC goes.

My rule of thumb is to match the video ram of your largest card, and then +1GB for the OS. For example, a 3GB 7970 or 280x works fine on 4GB (3GB for card, and +1GB for OS). A 290 has 4GB RAM, so you would need at least 5GB of system RAM (we use 8GB, and have never had any issues).

[Starscream]

I have come to the conclusion that the amount of system RAM required heavily depends on

• Thread concurrency
• Number of GPUs

I have also come to the conclusion that the system RAM is only required to create the kernel code that cgminer then transfer to the GPUs. In other words, once the kernels are built, you no longer need the system RAM *until* you change whatever parameter in cgminer that affects the kernel, then cgminer will need the RAM again to re-build the kernel.

I may be totally wrong though, asked and still looking for certainty about cgminer and system RAM requirements. Given that CK has now totally removed GPU support from cgminer, I didn't ask him directly (as doing so might be perceived uninformed/trollish)

You are correct, to an extent. It was my impression that the system memory was only used to build the initial kernel, which does get larger the higher your TC goes.

My rule of thumb is to match the video ram of your largest card, and then +1GB for the OS. For example, a 3GB 7970 or 280x works fine on 4GB (3GB for card, and +1GB for OS). A 290 has 4GB RAM, so you would need at least 5GB of system RAM (we use 8GB, and have never had any issues).

I got R9 290 and a total of 4GB RAM in my system and everything works fine.

[wsirianni1]

I have 5 7970s and 4 gigs of ram. Runs good sometimes it freezes but I'm not sure its the ram or the fact I'm over clocking the cards.

 Gigabyte modo 990fxa
Amd semperon 145cpu
Kingston 4g ram chip
Thermaltake 1200w PSU
Corsair 750 w PSU
All cards on risers.

[grippy54]

I have a 3 x R9 290 rig and a 4 x R9 290 rig, both with win 7 x64. I was not able to get either one to run at full speed with 4gb. I couldn't get sgminer to start with a high enough TC. They each limped along until I installed another 4gb each, then I could turn up to full speed.