290 in crossfire PCI-E speeds

[Beerbaron]

I have an P67A-GD65 motherboard which has Gen2 (1x16, 1x8) PCI-E slots. I currently have 1 Sapphire Radeon R9 290 4096MB. If I add a second card would the x8 speed PCI-E slot impact the performance of the card? I will be using it for gaming and mining.


Thanks.

 

[RJC]

I think if I remember correctly there is only a couple percent different in performance from dual 8x and 16x.

 

[setter]

The difference is miniscule tbh. I ran sli 670's in the spec in sig, (dual x8) and a dual x16 i7 930 setup. Fps in games were pretty much identical.

 

[Beerbaron]

Would that be the same for mining as well?

 

[Beerbaron]

Can I game with one card and mine with the other at the same time?

 

[Puppetmaster]

Can I game with one card and mine with the other at the same time?

Yes, just disable crossfire (can be done without disabling but it makes windows a bit laggy).

I run 290 for gaming and one for mining. Sometimes mine on both or game on both, depending on what I'm doing.


Im running both @ PCI-E 2.0 @ 8x and it seems fine for performance. For mining it doesnt matter, you could use x1 and have no difference.

 

[drunkenmaster]

Yup mining, no difference, I rarely bother playing on both 290's, just continue to mine on one, game on the other. With cgminer open you can just disable one gpu without turning it on/off, sometimes when closing and opening cgminer it will decide to not work on the gpu properly and default to the gpu until you reset the gpu driver.

So leaving it open(and with plenty of pools listed) and just disabling the gpu while gaming, I never have an issue.

In full on performance, a 4x pci-e 3.0 slot probably makes little difference. the 16/8x difference in pci-e 2.0 was never significant and 3.0 is twice the speed per slot, of course gpu's use a bit more bandwidth but ultimately there is more than enough.

 

[Beerbaron]

How do you set your config file to mine using a specific and both cards?

 

[Puppetmaster]

How do you set your config file to mine using a specific and both cards?

I just have set of values in the config / batch file as the cards are the same. Then in cgminer just disable a card, Press G > D then choose whichever card is the 2nd one (they are mixed up on mine so card 1 is primary, card 0 is secondary). To enable just do G > E > and the card.

 

[Beerbaron]

Can you paste your config so i can see it?


Thanks.

 

[Puppetmaster]

I use a batch file instead of a config but you can adapt it easily

Spoiler

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer --scrypt -o stratum+tcp://fast-pool.com:3333 -u Puppetmaster.mainpc -p abc -I 13 -w 256 --lookup-gap 0 --thread-concurrency 35960 --no-adl -g 1

You wont need the --no-adl unless you are using water / custom cooling on 290's.

It should work fine with any config. Normally if you are running different cards, you use "," so like 35960, 35960 or whatever but if you just leave it as one set of numbers both cards will use it. Just fire up cgminer and use the built in commands to disable a gpu. Once you are done gaming just re enable it.

 

[Beerbaron]

This is the contents of the batch file i'm currently using. What would i need to change?

Spoiler

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt -o stratum+tcp://wdc.ocukminingpool.com:3334 -u **yourusername**.**yourworkerid** -p **yourworkerpassword** -w 256 -v 1 -I 19 -g 1 -l 1 --thread-concurrency 29000

I have ordered a second 290 tonight.

 

[Stas823]

Don't the 290 go without a bridge? What impact does it have on crossfire being 8x pice 2

 

[Puppetmaster]

This is the contents of the batch file i'm currently using. What would i need to change?

Spoiler

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt -o stratum+tcp://wdc.ocukminingpool.com:3334 -u **yourusername**.**yourworkerid** -p **yourworkerpassword** -w 256 -v 1 -I 19 -g 1 -l 1 --thread-concurrency 29000

I have ordered a second 290 tonight.

I don't think you need to change anything. I have intensity set low and then up it, if for any reason you had to restart it while gaming 19 int will make the game un happy buy other wise it should be fine.

Don't the 290 go without a bridge? What impact does it have on crossfire being 8x pice 2

As far as I am aware, i dont think the lack of crossfire bridge makes any difference. for me Performance seems what I would expect.

 

[Beerbaron]

Don't the 290 go without a bridge? What impact does it have on crossfire being 8x pice 2

http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1227&lid=1&pid=2070&leg=0

The R9 290 Series has the ability to support AMD CrossFire Technology mode without the need for a hardware strap or “CrossFire ribbon”, while maintaining the same quality and performance that AMD CrossFire Technology is known to deliver.

Do i have 2 batch files, one for each card? I'm trying to understand how i manage the 2 cards.

I don't think you need to change anything. I have intensity set low and then up it, if for any reason you had to restart it while gaming 19 int will make the game un happy buy other wise it should be fine.

 

[Puppetmaster]

You use one batch file / config. When you start CG miner, both cards will be listed and will use the settings in the config / batch file. Above your speeds, it has things like

[P]ool Management [G]PU Management ettings [D]isplay options [Q]uit

So when you press g when cgminer is running, it will give you various options in the cgminer window.

[E]nable [D]isable ntensity [R]estart GPU

If you press "D" on the keyboard, it asks which card you want to disable. Normally you would have cards 0 and 1 listed so you would disable card 0 (primary) to game with. Sometimes cgminer gets it mixed up, (if i have crossfire enabled, card 0 is the primary card, crossfire disabled and cg miner thinks card 1 = primary card) You may need to check with afterbuner to work out which card is which in cgminer.

 

[Beerbaron]

My MSI P67 GD65 motherboard has the 2 PCIE slots too close together. I received my new card from OcUK today. Looking at it installed even with the ref cooler they would get too hot. I was looking to add an aftermarket cooler so will have to return the second card. There is not enough space between them to add an aftermarket cooler. No point running 2 cards that are going to be throttled. Might as well have one thats working at 100%.