why are my SLI 670's running at different speeds?

[Homer Simpson]

just tossed a couple zotac 4GB 670's in my system. naturally, both bought at the same time from the same place and have different bios versions. not sure if that is a factor or could be a potential problem. zotac doesnt have bios updates on their site. anyway, im playing some stuff tonight and i notice precisionX is reporting the cards running at different speeds. one is running at 1176 and the other 1202. the "faster" one is about 5C cooler. when i first start gaming they are both the same, 1202 and after a things warm up the warmer card runs a tad slower. temps are 65 and 60 respectively on the slow and fast card. is this normal for 600 series cards?

 

[Termie]

Yup, absolutely normal. You'll need to keep them under 70C or they'll start throttling. Given that they start out the same speed, it's clearly the temp on the hotter card that's throwing it out of sync.

 

[BTRY B 529th FA BN]

Which card is configured where, in the PCIe order from top to bottom?

 

[blackened23]

Completely normal with kepler cards. Every kepler card has a different boost speed, and in SLI they will run at different speeds.

 

[Homer Simpson]

i assume the top card is the hotter of the two. thats the way it was with my 570s. i was just playing some bf3 and the cards were running in the 50's but the warmer one was still slower. maybe the bios difference has different boost settings? i dunno. stuff runs fine so maybe its nothing to worry about.

 

[blackened23]

i assume the top card is the hotter of the two. thats the way it was with my 570s. i was just playing some bf3 and the cards were running in the 50's but the warmer one was still slower. maybe the bios difference has different boost settings? i dunno. stuff runs fine so maybe its nothing to worry about.

It's not a different BIOS if they're identical cards.. Again, every kepler has a different boost speed depending on chip quality, it's just how it is. No two kepler's are alike most of the time.

 

[Termie]

It's not a different BIOS if they're identical cards.. Again, every kepler has a different boost speed depending on chip quality, it's just how it is. No two kepler's are alike most of the time.

This is true, but he may able to compensate by dialing in different boosts in MSI Afterburner.

 

[Homer Simpson]

It's not a different BIOS if they're identical cards.. Again, every kepler has a different boost speed depending on chip quality, it's just how it is. No two kepler's are alike most of the time.

well, gpu-z says they are different versions. i know from reading the evga forums that bios updates were made to their 670's (i almost bough evga's). it appears zotac did the same but didnt make them available for consumer download. in the grand scheme of things, i suppose it doesnt really matter. if kepler's boost differently per card and its normal, that works for me. just seemed odd which is why i asked. i'd have thought that would jack up sli but so far everything runs great.