CPUs and GPUs (Oh My)

[Primeinator]

Originally Posted by M344587487

[*]The one forumite that's publically tried Big Navi sold it in frustration due to technical issues, it's only an option if don't mind being a canary. And if you have deep pockets

It looks like the 6900 XT is one of these "Big Navi"? What kind of issues did he/she have?

[M344587487]

Big Navi is all RDNA2 to date, 6800/6800XT/6900. The upcoming 6700XT may or may not be under that umbrella, the others were called big navi because they have more than the 40 CU's of the 5700/XT but the 6700XT is a direct replacement with 40 CU's.



Starting from this post in that thread xyzzy documented their efforts: https://mersenneforum.org/showpost.p...&postcount=103



Their problem may or may not have been resolved by the power cycling code that was implemented after they'd gotten rid of the card. AFAIK no one else has acquired a card since to test.

[Primeinator]

Originally Posted by M344587487

Big Navi is all RDNA2 to date, 6800/6800XT/6900. The upcoming 6700XT may or may not be under that umbrella, the others were called big navi because they have more than the 40 CU's of the 5700/XT but the 6700XT is a direct replacement with 40 CU's.



Starting from this post in that thread xyzzy documented their efforts: https://mersenneforum.org/showpost.p...&postcount=103



Their problem may or may not have been resolved by the power cycling code that was implemented after they'd gotten rid of the card. AFAIK no one else has acquired a card since to test.

*googles 'CU's*
What is the significance of this? Per the link it looks like Xyzzy was getting the expected microseconds/iteration George provided in his link... or should it have been faster than this?

[M344587487]

A CU is a compute unit, a cluster of cores and some other bits. Similar to how Nvidia talks in SM's. You can only directly compare SM's or CU's in relation to other cards in the same generation.



IIRC Xyzzy's issue was that for some reason the card failed to queue new work and needed resetting every day or so. Details in the thread: https://mersenneforum.org/showthread...679#post568679

[Primeinator]

Originally Posted by M344587487

A CU is a compute unit, a cluster of cores and some other bits. Similar to how Nvidia talks in SM's. You can only directly compare SM's or CU's in relation to other cards in the same generation.



IIRC Xyzzy's issue was that for some reason the card failed to queue new work and needed resetting every day or so. Details in the thread: https://mersenneforum.org/showthread...679#post568679

I imagine then that the 6900 XT is similar enough it would be plagued with a similar problem?