CPU for a silent high performance PC - i7 4790 or 4790k?

All about them.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Mon Jan 05, 2015 7:16 am

Hello everyone,

As in title, I'm looking to get one of these CPU's for a new build.
I am certain that I'm not going to OC even to the smallest extent, but that's the reason exactly I'm eyeing the 4790K: It's 400Mhz faster at stock speeds.

1) Do you think that the additional horsepower worth the a-little-more-than-50$ (where I live at least) price margin the 4790K has over the 4790?
2) The 4790K has a TDP of 88w while the 4790 sports 84w TDP. Is that significant when planning a silent rig? I'm going to use Scythe Kotetsu as the cooler.

Thanks in advance.

edh
Posts: 1621
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by edh » Mon Jan 05, 2015 8:16 am

What is your intended usage? If its gaming, you don't need an i7 as games generally aren't that well multithreaded. For gaming i5 makes the most sense.
Last edited by edh on Mon Jan 05, 2015 11:19 am, edited 1 time in total.

sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Mon Jan 05, 2015 9:46 am

Heavy multi-tasking, and some gaming.
But anyway I'm convinced I'm going with either one of those CPU's, question is - which one exactly.

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by CA_Steve » Mon Jan 05, 2015 11:09 am

Without knowing your "heavy multi-tasking" applications, any specific advice from us is worthless. So, compare the twohere. Decide for yourself if your particular tasks benefit. Compare your current cpu vs them as well.

As for cooling at stock speeds with the Kotetsu, either CPU is fine.

sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Mon Jan 05, 2015 11:21 am

Thanks for the input... that's a great link! I wasn't familiar with that great tool...

Well, the K is faster but not by a considerable margin (I think). Since the price differences is not so big I might opt for it, but I'm just worried about the extra 4 watts to the TDP (totaling in 88w), that could make the cooling (silently) of the CPU harder.

cerbie
Posts: 46
Joined: Sat Dec 28, 2013 3:21 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by cerbie » Mon Jan 05, 2015 12:28 pm

Does some gaming include a video card? If so, and the extra speed may not be worth it, look at dropping down to near i5 costs, with a Xeon E3-1231V3.

edh
Posts: 1621
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by edh » Mon Jan 05, 2015 1:14 pm

sentry wrote:Thanks for the input... that's a great link! I wasn't familiar with that great tool...
Also try comparing the i5 and i7 with that tool. Not a lot of difference on many tests.

sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Mon Jan 05, 2015 10:13 pm

Thanks for the replies.

I do have a video card.

The main (actually, the only) thing that stops me from grabbing the 4790K is extra 4 watts in its TDP.

Is that significant? Will it introduce hardships in cooling it silently?

I'm modeling my rig after the recent "Quiet ATX Gamer, R5 version". I'll be using the Scythe Kotetsu as recommended, but if I'm going the 4790K route, we're dealing with a 88w TDP CPU, while the guide specifies a CPU with a TDP of 84w.

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by MikeC » Mon Jan 05, 2015 10:39 pm

88w vs 84w? No difference whatsoever.

The only time such a small TDP dif. would lead to a hotter/cooler CPU would be other factors like...

1. the die is smaller thus one has higher thermal density
2. worse thermal connection between heatspreader & die = poorer cooling

sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Mon Jan 05, 2015 10:50 pm

1) I assume the die is same sized in both the 4790 and 4790K, right?
2) I guess as long as everything is installed properly, condition 2 will not exist, correct?
3) In conclusion - from a SPCR point of view, could the 4790K be placed in the Quiet ATX Gamer (R5 version) build, instead of the Intel Core i5-4670K, and be a suitable choice in the thermal and acoustic context?

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by MikeC » Mon Jan 05, 2015 11:47 pm

3) sure, no prob. 8)

cerbie
Posts: 46
Joined: Sat Dec 28, 2013 3:21 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by cerbie » Tue Jan 06, 2015 6:41 am

sentry wrote:1) I assume the die is same sized in both the 4790 and 4790K, right?
Yes. All of the Devil's Canyon desktop Core i5, Core i7, and Xeon E3 CPUs are identical. The diferences are entirely features and binning.
2) I guess as long as everything is installed properly, condition 2 will not exist, correct?
Small variations are normal. Too little pressure could lead to problems that don't show up under normal conditions, but that should be rare, with a cooler from any reputable maker.
3) In conclusion - from a SPCR point of view, could the 4790K be placed in the Quiet ATX Gamer (R5 version) build, instead of the Intel Core i5-4670K, and be a suitable choice in the thermal and acoustic context?
Yes. The price/performance difference is substantial, the power consumption difference is negligible, and user-controllable. If the 4W bothers you, set yours to 84W :).

Abula
Posts: 3662
Joined: Tue Nov 02, 2004 12:22 pm
Location: Guatemala

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by Abula » Tue Jan 06, 2015 7:34 am

Really comes down to what you want and need, i always end up buying K CPUs as for me its much easier to sell them later, most of my friends do overclock and will not consider a none K cpu, that said, either choice is good. Under the same clocks and voltages the CPU should run very similar temperatures, and both can be underclocked for even lower temperature.

Now i really like my 4970K, i can run at 4.4ghz with simply enabling enhanced turbo on my MSI, its simply an overide of the max clocks per core and allows the full 4.4 on all cores running, that said under extreme load like Prime95 it goes to 90C+, so i restricted it to 4.2ghz on the enhanced turbo, and now i sustain sub 90c under prime95, this are very unlikely scenarios, under normal all day conditions i never reach 70C, now if you do render/encode you might see higher, but gaming and every day tasks the cpu runs very cool and its very efficient to finish the tasks and return to idle states (depends into how you set it up).

I would worry more into getting a good case with good ventilation and a good motherboard that allows you control fans, and thus the choice of fans will depend on this things.

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by quest_for_silence » Tue Jan 06, 2015 8:52 am

sentry wrote:3) In conclusion - from a SPCR point of view, could the 4790K be placed in the Quiet ATX Gamer (R5 version) build, instead of the Intel Core i5-4670K, and be a suitable choice in the thermal and acoustic context?
If you're enough brave, delid the CPU and shave off silently 15°C on load.

sentry
Posts: 24
Joined: Thu Aug 06, 2009 1:50 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by sentry » Tue Jan 06, 2015 10:22 am

Pardon me, but what's to "delid"?

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by quest_for_silence » Tue Jan 06, 2015 10:43 am

sentry wrote:Pardon me, but what's to "delid"?

It's the removal of the CPU IHS in order to substitute the thermal interface material: http://www.silentpcreview.com/IvyBridge ... nd_results

cerbie
Posts: 46
Joined: Sat Dec 28, 2013 3:21 pm

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by cerbie » Tue Jan 06, 2015 11:11 am

quest_for_silence wrote:
sentry wrote:Pardon me, but what's to "delid"?

It's the removal of the CPU IHS in order to substitute the thermal interface material: http://www.silentpcreview.com/IvyBridge ... nd_results
But, Devil's Canyon has better TIM, so it wouldn't be as much of a difference, on top of the procedure being risky. IB and initial Haswells were known for not having the best TIM on the IHS.

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by quest_for_silence » Tue Jan 06, 2015 11:32 am

cerbie wrote:But, Devil's Canyon has better TIM, so it wouldn't be as much of a difference
AFAIK it is always worthwhile.

Just for instance, that's a typical application on a 4790K: so, you see @stock before delidding 69-72°C, while @stock after delidding 57-60°C (-12°C on average).

edh
Posts: 1621
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by edh » Tue Jan 06, 2015 11:46 am

quest_for_silence wrote:
cerbie wrote:But, Devil's Canyon has better TIM, so it wouldn't be as much of a difference
AFAIK it is always worthwhile.

Just for instance, that's a typical application on a 4790K: so, you see @stock before delidding 69-72°C, while @stock after delidding 57-60°C (-12°C on average).
What I'd be interested to see is what the difference would then be if you put the IHS back on again. Does it become that much worse again? Does the application technique or thermal paste make that much of a difference? A few years ago I found this great page of car performance tuning myths written by a very experienced automotive engineer and one thing he stated is that you can only count on tuning giving an improvement if you are able to undo the change and prove that the improvement goes away, otherwise there could be other reasons for the improvement that you don't see.

As a scientist I'm sceptical of such small sample results. 12C might sound like a big difference but as each original temperature measurement is +/- 1C anyway, the difference becomes 12+/-2C even if you assume 1C accuracy. Yes, there might be some improvement, but you can't say that it is universal for all cases. It would be more accurate to say 'around 10C' rather than to say 12C.

Maybe a little bit off topic and I'm not doubting there is some improvement but I just wouldn't jump to any conclusions about how big an improvement there might be. Do more tests, take averages, calculate experimental uncertainties. :D

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by quest_for_silence » Tue Jan 06, 2015 12:50 pm

edh wrote:Maybe a little bit off topic and I'm not doubting there is some improvement but I just wouldn't jump to any conclusions about how big an improvement there might be. Do more tests, take averages, calculate experimental uncertainties. :D

The net is full of similar setups, dig into it.

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by CA_Steve » Tue Jan 06, 2015 4:01 pm

What we'll never see posted are stats on the success rate for delidding w/o catastrophic results :D

alecmg
Posts: 204
Joined: Thu Mar 13, 2008 5:56 am
Location: Estonia

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by alecmg » Tue Mar 24, 2015 4:29 am

sentry wrote:2) The 4790K has a TDP of 88w while the 4790 sports 84w TDP. Is that significant when planning a silent rig? I'm going to use Scythe Kotetsu as the cooler.
Unlike all previous K processors, 4790K has faster clocks than its sibling (4/4.4GHz vs 3.6/4GHz), leading to increase in performance and power. Its kinda factory overclocked already.
If you manually drop clocks and volts it'll be no worse than regular. But by default the difference will be much more than 4W under load

nagi
Posts: 125
Joined: Tue Aug 31, 2010 6:48 pm
Location: Outside the box

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by nagi » Thu Jun 25, 2015 8:03 pm

edh wrote:What is your intended usage? If its gaming, you don't need an i7 as games generally aren't that well multithreaded. For gaming i5 makes the most sense.
Actually, now that the new gen consoles are also heavily multicore, the PC games are becoming increasingly multithreaded. Granted, they only have 6(?) cores for the games to utilize, but that's still more than threads an i5 has.

CA_Steve
Moderator
Posts: 7650
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by CA_Steve » Thu Jun 25, 2015 8:41 pm

While games may becoming more multi-threaded, the performance bump using the extra threads is still very limited past 4 physical cores....and the vast improvements in reduced CPU overhead for DX12/future OpenGL/Metal API for MacOS will bring a decent bump in current CPU performance. In the end, it's the gfx card that's the performance limiter, not whether you have an i5 or i7.

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by quest_for_silence » Thu Jun 25, 2015 11:33 pm

CA_Steve wrote:In the end, it's the gfx card that's the performance limiter, not whether you have an i5 or i7.

Not to mention that IPC matter, a lot (I'm referring to those 6 console's cores, or to any AMD core).

Rasbelin
Posts: 31
Joined: Mon Jul 25, 2005 9:05 pm
Location: Finland

Re: CPU for a silent high performance PC - i7 4790 or 4790k?

Post by Rasbelin » Mon Jul 13, 2015 7:12 am

I'd say Core i7 4790T. :) That's what I'm typing this with.

Went with the T model to avoid underclocking like on my previous Core i5 (Ivy Bridge) setup. Much more straightforward and no need to worry anout mobo options (are there or not). I'm running this with a Asus CS-B (Intel Q87) mobo and in a very cheapo MATX case. I still however need to install one more fan and change the PSU, as the fanless Seasonic makes an awful electric hiss all the time. Just listen to anything classical with a slow tempo and you're more like listening to the PSU nonstop. :roll:

It all comes down to A) how often do you play and B) which genre are those games, not to mention how new are they?

Post Reply