HD7870 Tahiti Edition

Message boards : Number crunching : HD7870 Tahiti Edition

Author	Message
JB Volunteer tester Send message Joined: 21 Jul 09 Posts: 24 Credit: 5,888,477 RAC: 29,807	Message 1332988 - Posted: 30 Jan 2013, 23:44:52 UTC
	In Dec/2012 I bought the new HD7870BB-Tahiti Edition card for my rig. Now this card completes one Astropulse in 40mins thru Lunatics 0.40. (Means two APs in 80mins with count=0.5 and device=2) Not OC'ed. Have anybody else made some experiences with this single GPU since release ?
	ID: 1332988 ·

skildude Send message Joined: 4 Oct 00 Posts: 8970 Credit: 37,778,326 RAC: 42,961	Message 1333001 - Posted: 31 Jan 2013, 0:36:29 UTC - in response to Message 1332988.
	yes my 7970 can handle 3 WU's at a time. However for optimal throughput I keep 2 CPU cores idle to feed the GPU ____________ Proud member of TSWB. End terrorism by building a school
	ID: 1333001 ·

JB Volunteer tester Send message Joined: 21 Jul 09 Posts: 24 Credit: 5,888,477 RAC: 29,807	Message 1333016 - Posted: 31 Jan 2013, 1:00:18 UTC
	Also. Few weeks ago I switched my cpu load to 1.00CPUs+0.50GPUs per ap wu. Based on HTmode so these are 2 logical cores.
	ID: 1333016 ·

cov_route Send message Joined: 13 Sep 12 Posts: 85 Credit: 1,731,163 RAC: 2,762	Message 1333017 - Posted: 31 Jan 2013, 1:13:16 UTC - in response to Message 1332988.
	Have anybody else made some experiences with this single GPU since release ? I don't have that card, I have a 6670. You have 4 times more compute units than me, you have cgn and I have vliw 5, your memory interface is 256 bits mine is 128, your clock is 925/975 I'm at 810. All in all I'd expect you to be running ap 3 to 5 times faster than me, maybe more. But you are only about 2.5 times faster. You can speed this thing up. Check your GPU utilization, if it's not at least 70%, idle a core to feed the gpu. Also you may need to tune the command line parameters unroll, ffa_block, ffa_block_fetch. My experience was that unroll in particular had to be set properly (I use 8, might be a function of the number of compute units you have, which is 20 in your case).
	ID: 1333017 ·

JB Volunteer tester Send message Joined: 21 Jul 09 Posts: 24 Credit: 5,888,477 RAC: 29,807	Message 1333026 - Posted: 31 Jan 2013, 1:30:39 UTC - in response to Message 1333017.
	Have anybody else made some experiences with this single GPU since release ? ...Also you may need to tune the command line parameters unroll, ffa_block, ffa_block_fetch. My experience was that unroll in particular had to be set properly (I use 8, might be a function of the number of compute units you have, which is 20 in your case). At this time my parameters in the app_info.xml are switched to: <cmdline>-instances_per_device 2 -unroll 12 -ffa_block 8192 -ffa_block_fetch 4096 -sbs 128</cmdline> In the next days I'll try to set the values higher.
	ID: 1333026 ·

Message boards : Number crunching : HD7870 Tahiti Edition