Enable HT on i7???

[SwaleSmith]

Hi,

Have been doing some tweaking with my i7 and have found that with HT disabled I am able to run higher clock speeds and or lower volts.

But what I'm wondering is this, am I better to use HT and go for a lower clock speed or have HT off and have higher clock speed?

Can't help that think this, I only really play games and use my PC for simple non intensive app's and it is of course common knowledge that there are very few games or app's for that matter that could even utilize a quad core yet alone another four ''virtual cores''

I am running my cpu @ 4ghz at the moment with HT off and am pleased with the performance boost and fail to see any point to makeing my cpu hotter and loosing clock sped for another 4 virtual cores.

Any Thoughts????

Thanks in advance.

 

[monkey7]

As long as you are not running any quadthreaded applications, turn it off. When running 4+ threaded intensive applications the HT will get you some serious performance gain in my experience.

When I run a F@H SMP with HT off or on doesn't make much of a difference. When I start watching a movie however, the SMP doesn't seem to be losing a lot of performance when the HT is enabled. When I disable the HT performance loss is fairly larger.

 

[SwaleSmith]

I see, just couldn't get my head around the fact that if you only actually have four physical cores how can another four that are not there be of any real gain as I guess it most go through the physical cores in the end??

So anything that uses 4 cores or less (quad optimized games etc) HT of will be fine but If use something that makes use of more than four threads it's better on.....thought nothing really used more than four threads?

 

[VonBlade]

Fritz Chess, various rendering packages and TPMG use as many cores as you have.

 

[monkey7]

The SMP uses 4 threads so that fills everything up. As soon as you start antoher application along with a 4threaded application HT already starts to pay off.

And as VonBlade said: most rendering packages etc. are programmed to use any cores available. My cpu usage jumps from >1% to 100% if I start rendering with AutoCAD.

 

[SwaleSmith]

So I should have i on if I can, and there is certainly no performance loss by having it on vs off at the same frequency, and would a loss of 100mhz or so be worth it if it ment having HT enabled???

Have some people saying and infact if I remember correctly pc format or custom pc did a review on I7 in ther xmas issue saying that windows vista could not tell any difference between physical and virtual cores and some times windows would assign tasks to virtual cores when it should be at a logical core, is this right or again do the pros out way the cons???

bareing in mind my use is only gaming and O.S

 

[monkey7]

With OS/game only I'd go for HT off. It's mainly meant for heavily loaded cpu's.

And about the wrong thread/cpu assigning by Vista, I never noticed it and wonder if it makes any noticable performance difference at all.

 

[Tweaker]

I have noticed it does add temp, but i dont need additional volts for it to be stable, I left it on as while it does add heat, not so much that its dangerous. My CPU is 1.28 in bios, 1.25 in CPU-Z and running at 3.8ghz, temps on idle about 40-45 load 55-60 on air.

 

[Pyr0]

i'm thinking about leaving mine disabled as it takes much more voltage to keep it stable at 4GHz+ with HT (and my chip's pretty crap lol)

 

[SwaleSmith]

I can run it with my cpu @ 3.8ghz with just 1.25vcore but after that I start needing masses of volts, and then it pushes my temps up.

As I feel the performance has not been hurt if anything, for my use it might be fair to say its improved it, I have left it offf and am runnign my cpu @4ghz (20x 200bclk) with 1.3875vcore and 1.2875 qpi might be able to get to a 4.1ghz but for speed vs performance vs heat I think this is a good balance for me, I have noticed considerable improvement over 3.8ghz with HT On so think im gonna stick at these settings

 

[kataras]

This review will give you an idea of how much performance is gained/lost with ht in certain apps and of course games

 

[SwaleSmith]

That proves it Im defiantley sticking with higher clocks and HT Off