View Full Version : How many disable HyperThreading on I7?
07-16-09, 07:08 PM
The way I see it is as follows :-
PROs of disabling HT
1) Lower Heat
2) Lower power consumption
3) Higher overclocks with less volts
4) Higher IPC, ie they run anywhere from 1-10% faster with HT not using resources in software which doesn't use 4 threads (most software), especially in games (http://ixbtlabs.com/articles3/cpu/ci7-turbo-ht-p2.html).
CONs of disabling HT
1) Task Manager doesn't show 8 cores
2) Video encoding and software 3D is slower
I've disabled HT on my I7's, anyone else?
07-16-09, 10:15 PM
So long as I can hit 4ghz with HT enabled I will leave it on.
07-16-09, 11:11 PM
I hear it helps alot for ocing but im doing about 4 and i keep it on.
07-17-09, 02:43 AM
I leave it enabled. Something about disabling it just seems wasteful to me, I mean if I wanted a high clocked core 2 quad (basically what no HT is), I could have kept my QX9650. Maybe I'm just stubborn but I prefer to leave it on because that's what makes an i7 an i7.
Past 4GHz there isnt much noticable improvement except in encoding and synthetic benchmarks. HT helps in the the benchmarks I run most often, and it definetely helps in encoding, so I'm not really going to lose sleep over a couple lost fps here and there to HT or lost overclocking potential beyond what I currently run. As long as I can keep the heat under control, there's no reason for me to disable it.
When i7 was released alot of publications claimed little beneift came with leaving HT enabled, and worse performance in some cases. I'd be curious to know if that's changed at all with new software since then.
07-17-09, 07:03 AM
Turbo = off
Speedstepping = off
HT = on
07-17-09, 01:07 PM
I have it disabled for temp reasons... makes ~10C difference and from that I can profit every day. Can't say I'd use HT every day. Sometimes it's even slower, especially in games.
Uberpwnage, in my opinion the main i7 feature is the triple channel IMC, not HT.
I would agree with you on that, except it seems Intel thinks otherwise.
LGA 1156 processors will be labeled i7 if they have HT, if not, they get the i5 branding. All LGA 1156 processors are limited to dual channel DDR3.
07-17-09, 04:33 PM
Just leave it on, it makes no sense disabling it cuz why if you paid good money for a cpu, than use it for whats its designed for. Kicking some serious bigman ass.
Apparently :p I makes sense for them to use it as a feature for marketing but IMO it's not that big of a deal.
I also leave it off even though I do a lot of photochopping and 3d studio max, because of temp reasons; HT causes a serious overheating of the cores when clocked beyond 4Ghz.
07-17-09, 06:32 PM
Turbo = off
Speedstepping = off
HT = on
07-17-09, 09:13 PM
I've ran it both on and off benchmarking vantage. With HT enabled I get a higher CPU and total scores but lower CPU overclock and GPU score. So I bench with it on and game with it off.
07-24-09, 11:52 PM
I turned it off once, but to be honest, for whatever improvement I may get in some corner cases (Far Cry 2 for instance) is completely offset by the fact that my general windows experience becomes so much worse. Running 4 cores sucks. HT on surprised the hell out of me; I didn't think I'd notice any improvement. This is before we start talking about application specific improvements; I'm just speaking of opening a few programs, browsing the internet while playing tunes, etc. I can run 1080P movies side by side a window, and have no lag, dropped frames. I can do that while installing something. With HT off, everything turns into a stutter fest.
07-25-09, 12:22 AM
i have it on currently, i hit 4.0ghz with no issue, bu I have it on 3.8ghz now because of lower temp.
08-08-09, 05:42 PM
IMO with a CO stepping turning the HT off helps you overclock a lot better ,but with a DO stepping I can'nt tell no difference.
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