CPU CPU selection question

[Kmpkt]

I'm looking at doing an NFC build in the not too distant future and I find myself wondering whether an i3 CPU might be a good choice for the build. Apart from the obvious problem of not being able to overclock an i3 (which I probably wouldn't bother trying anyhow given case thermals) are there any other major drawbacks to using an i3 4360 versus my 4670k or 4790k. The potential upside in my mind would be more wattage available to the GPU as well as better thermals with regards to the CPU. Any comments would be greatly appreciated.

 

[confusis]

Have you considered the 'T' variants of the i5/7's?

 

[K888D]

I would expect that putting the 30W TDP saving from downgrading your CPU towards a 30W higher GPU would be a better use of the limited power availability for gaming performance.

In other words a low power CPU is less likely to be a bottleneck in gaming than a low power GPU.

 

[Kmpkt]

Have you considered the 'T' variants of the i5/7's?

I hadn't, but only because I already own the i3 chip in question. Looking at the 35W TDP of the i5/i7 and the 54W TDP of the i3 would it be a fair assumption that in a real world situation, the i5/i7 would give another 20W of headroom and can anyone comment on whether or not the performance would be similar or better by going with a T variant chip?

After a bit of research, it appears that the i7 4765T is a pretty good low wattage choice.

 

[Kmpkt]

So these chips seem to be very scarce and about 50%+ more expensive than their non-T counterparts. Anyone have a lead on where to get these at more comparable prices to the K and normal series processors?

 

[GuilleAcoustic]

I recently bought an i7-4785T (4 cores, HT, 2.2GHz, 3.2GHz turbo, 35W) from the bay for 200GBP. Very happy with this CPU, only waiting for september (bday) to get a GPU.

I was using an i5-4570 (84W) prior to that and noticed no real-world perf loss. The CPU is cooler and my motherboard VRMs run cooler too (less watts to provide).

 

[QinX]

I've got a 4790K and a 4785T and recently did some testing for someone on another forum.
You can see the difference in efficiency quite clearly.
I also though T-series where the same price or marginally more expensive, but it seems supply and demand are not in your favour.
The 6700T should in actually be $30 cheaper.

It's a dutch screenshot, Tijd = Time and Gemiddelde = Average.
The Benchmark was Cinebench R15 and I've only run the Multithreaded test.
My rough conclusion was that the 4785T performs 89% better per W compared to the 4790K.
Or for 1/3 of the power you have 2/3 of the performance.

I'm fairly curious what the 4790T would have been like. it's 45W but it does turbo 0,7Ghz higher up to 3,9Ghz.

 

[Kmpkt]

That is pretty insane. I reckon given the clocks on the 4790T, it would likely be a much better gaming chip (games love clock speed right?). Thanks so much for the info and I think I might bite the bullet on a 4790T in the not too distant future.

 

[MrTiny]

Alternatively, you can undervolt any one of your CPUs. Managed to undervolt an i7 6700 down to 40 watts quite successfully. Similar tdp when undervolted, higher clock speeds, and you won't have to pay extra since you already have it. You could use a combination of underclocking and undervolting on one of your current chips to achieve a similar TDP and still hit higher clocks than a T variant. Best part is no chance to fry the chips since you are reducing TDP.

 

[alex1577]

Alternatively, you can undervolt any one of your CPUs. Managed to undervolt an i7 6700 down to 40 watts quite successfully. Similar tdp when undervolted, higher clock speeds, and you won't have to pay extra since you already have it. You could use a combination of underclocking and undervolting on one of your current chips to achieve a similar TDP and still hit higher clocks than a T variant. Best part is no chance to fry the chips since you are reducing TDP.

With you on that one. I was able to take my 4790k down to 55 watts by underclocking to 3.6ghz with .93volts. I lost 10% performance, but also lost 50% max wattage at the same time.

 

[Kmpkt]

For anyone looking for an affordable T-Series Haswell I managed to find this listing on eBay

http://www.ebay.ca/itm/Intel-CM8064...357719?hash=item2a5eef2697:g:CiYAAOSwZG9Wisko

Brand new processors straight from the tray and actually close to MSRP versus 150+ over. Potential downside is 45W draw instead of 35W, but the upside is a decently high clock speed when compared to the 4785T and 4790T (should yield better real world performance than the former of these two). Also worth mentioning is this is a Devil's Canyon era chip which I believe means a better TIM under the IHS and hopefully better heat dissipation.

 

[Kmpkt]

Anyone here running (or have run in the past) a 35 to 45W CPU with a ~120W GPU like a GTX 960? I'm trying to figure out how comfortably I could run a 1060 and say 4690T on a 250W HDPlex combo or maybe even 160W combo?

 

[QinX]

Anyone here running (or have run in the past) a 35 to 45W CPU with a ~120W GPU like a GTX 960? I'm trying to figure out how comfortably I could run a 1060 and say 4690T on a 250W HDPlex combo or maybe even 160W combo?

I've run a 4670 with a GTX970 on the 250W HDPlex and a Voodoo 350W PSU. So I wouldn't worry about anything with a lower power draw. the 160W HDPlex would be interesting to see with the GTX960 and a 4690T, but I would think it will not pose a problem if it has similar over spec performance.