Buy a 4C8T 4.2GHz i7-6700k equivalent skylake CPU for merely 110 us dollars?

[imluvian]

I was using a second-handed i7-2600k@4.2GHz as a low-cost rig for 7*24 heavy CPU load tasks. I've been considering switching to Intel skylake CPUs for the higher AVX instruction efficiency and low power consumpotion, but the high cost of a brand new skylake i7 just doesn't fit the idea of low-cost, and other skylake CPUs may even not have same horsepower comparing with my old overclocked 2600k, until recently I found a "i7-6400t" for sale on Taobao (Chinese version of eBay). Its price is ￥720 which is about 110 USD. The actual model on the back of this CPU says "Intel confidential QHQG 2.20". Here is the CPU with my Asrock Z170 extreme4:

 

Take a closer look to the CPU:

Thanks to the "sky OC" feature of Asrock motherboards, I was able to OC it to 4.5GHz@1.3v by overclocking BCLK, but my crappy water cooling (coolermaster 120V) was not able to handle the heat. Then after some tweaking, I settled it to 4.2GHz@1.23v, here is the CPU-z (sorry for not using an English version):

And this is the CPU-z benchmark result, comparing with i7-6700k:

 

It seems so far so good, but there are some drawbacks after overclocking the BCLK:(maybe caused by my wrong BIOS setting?)

1. The CPU runs always at its highest clock speed, which would cause higher idle power consumption. Considering my rigs run 100% load almost all the time, this is not an issue for me.

2. The CPU temperature (80℃) is much more higher running scientific computing (mostly AVX instructions) than running AIDA64_5.70 FPU stress test (about 65℃). According to the best of my acknowledge, the CPU tempreature usually peaks when running AIDA64_5.70 FPU stress test. Are all the skylake CPUs like this or just because I am using an ES CPU?

3. CPU core temperatures can not be read my AIDA64 correctly (show 100℃ always), but CPU package/CPU IA Cores/GT Cores temperatures can be read correctly.

4. The iGPU does not funtion correctly. I use a HD6450 (also very low-cost)instead.

 

The AVX tasks run 40 freaking percent faster (I was expecting 20%) than my old rig. I've run it full load for 72 hours, and it has not crashed yet. The CPU virtualization also runs well. Overall I am pretty satisfied with my new rig. 

 

 

[ZetZet]

engineering sample, not supposed to be sold

[imluvian]

Just now, ZetZet said:

engineering sample, not supposed to be sold

I knew it. But always, some of them will end up in some random market

[crystal6tak]

Very nice find! Does Taobao ship world wide or something? That's insanely good performance to price ratio.

[Rune]

Yeah...anything with "intel confidential" on it is a no-go. Those samples are put through hell.

[imluvian]

3 minutes ago, Rune said:

Yeah...anything with "intel confidential" on it is a no-go. Those samples are put through hell.

Mine was brand new. There was no any indentations on the back of the CPU (there will be inevitable indentations once the CPU is installed), and the metal contacts on the back of it also seemed pretty new. 

[Orangeator]

7 minutes ago, imluvian said:

Mine was brand new. There was no any indentations on the back of the CPU (there will be inevitable indentations once the CPU is installed), and the metal contacts on the back of it also seemed pretty new. 

Link to where you bought it? Like I see them all over them all over the site, which seller did you buy yours from? 

[imluvian]

19 minutes ago, Orangeator said:

Link to where you bought it? Like I see them all over them all over the site, which seller did you buy yours from? 

http://b.mashort.cn/h.LvzXh?cv=AAEEyEnR&sm=111711

this site may not have an English version. 

[scottyseng]

1 hour ago, imluvian said:

-snip-

1. Try checking the Window's power plan options. You might need to go to advanced settings for the high performance power plan and change the minimum processor state to 0% (For the high performance plan, Windows locks this to 100% for some odd strange reason...which is the same as running it at full clock speed).

 

2. AVX is very hard on the CPU. It makes the CPU get very hot. All CPUs are kind of like this when reacting to AVX instructions (Some Intel CPUs on the stock turbo boost will boost to a lower speed because AVX is that hard on the CPU). If you really want to cook the CPU, go use Intel Burn Test (I don't think I've had any CPU stress test get the CPU so hot). But yeah, AID64 is mostly reflective of real world use, your scientific calculation is a step above that.

 

3. Hmm, that's a bit worrying, but keep in mind that ES samples were samples that were used in any kind of testing to set a standard for the retail processors. It might've been overclocked to it's end of life for testing. That might've caused damage to the sensors. That or it's running a buggy stepping revision of the CPU instructions (ES processors are testing processors after all...they don't have the latest stepping version usually).

 

4. I guess your ES sample had the iGPU killed for some reason...But yeah, AVX on Skylake is quite a bit faster.

 

I myself bought a Xeon E5-2695V3 for $600 (14 core, 28 thread @ 2.2 GHz) and it's been running fine for me in my NAS for 24/7 load. I have noticed that it does not reach the full turbo speed at all though (Not a cooling issue either...). But it still is around 3x the speed of my 2500K OC'd to 4.6GHz. And it beats out my cousin's 5820K @ 4.5 GHz while using a lot less power (This thing runs at 0.86 vCore under full load....crazy).

[imluvian]

9 hours ago, scottyseng said:

1. Try checking the Window's power plan options. You might need to go to advanced settings for the high performance power plan and change the minimum processor state to 0% (For the high performance plan, Windows locks this to 100% for some odd strange reason...which is the same as running it at full clock speed).

 

2. AVX is very hard on the CPU. It makes the CPU get very hot. All CPUs are kind of like this when reacting to AVX instructions (Some Intel CPUs on the stock turbo boost will boost to a lower speed because AVX is that hard on the CPU). If you really want to cook the CPU, go use Intel Burn Test (I don't think I've had any CPU stress test get the CPU so hot). But yeah, AID64 is mostly reflective of real world use, your scientific calculation is a step above that.

 

3. Hmm, that's a bit worrying, but keep in mind that ES samples were samples that were used in any kind of testing to set a standard for the retail processors. It might've been overclocked to it's end of life for testing. That might've caused damage to the sensors. That or it's running a buggy stepping revision of the CPU instructions (ES processors are testing processors after all...they don't have the latest stepping version usually).

 

4. I guess your ES sample had the iGPU killed for some reason...But yeah, AVX on Skylake is quite a bit faster.

 

I myself bought a Xeon E5-2695V3 for $600 (14 core, 28 thread @ 2.2 GHz) and it's been running fine for me in my NAS for 24/7 load. I have noticed that it does not reach the full turbo speed at all though (Not a cooling issue either...). But it still is around 3x the speed of my 2500K OC'd to 4.6GHz. And it beats out my cousin's 5820K @ 4.5 GHz while using a lot less power (This thing runs at 0.86 vCore under full load....crazy).

Sorry to say so but most of your guesses are incorrect.

The CPU is just a dull 4C8T skylake CPU runs at 800MHz to 2200MHz, and turbos to 2400MHz (yes, it does have a turbo boost) before overclocking the BCLK. Its clock rate changes according to the CPU load correctly, and all the core temperature can be read in AIDA64.

It acts pretty much like that you would expect an "i7-6400t" acts as long as you give it 100MHz BCLK.

[harrynowl]

12 hours ago, Rune said:

Yeah...anything with "intel confidential" on it is a no-go. Those samples are put through hell.

Not necessarily.

[harrynowl]

The iGPU will cease to function around 103 BLCK IIRC. Those T cpus are binned for low leakage so they should be a bit cooler than your average sample, but it's still an early/imperfect batch. That particular one was made on the first week of 2015.

[Coolheet]

I Just bought the same cpu for $90 NEW. Pretty excited.

[TheDouser]

Does this CPU not get the Intel  microcode other Skylake non k CPU's get that removes the non K ability to overclock? I been wondering since its a ES that maybe it does not get the Intel updates that the others got. here a link to what i'm talking about http://www.pcgamer.com/intel-puts-a-stop-to-overclocking-on-non-k-skylake-cpus/

 

Also i would like to note that even though the ASRock BIOS updates will remove the Sky OC feature i'm sure you can still stay with the old BIOS version or roll back but of course that comes with the cost of performance that could come with the more updated BIOS which i read that the same patch that removed the Sky OC also adds a performance boost or something.

[Sharif]

I will purchase mine tomorrow looking forward to overclock that guy~ 

[m1s7erh]

Could OP, or anyone who has one of these post a HWBOT x265 benchmark score? I'm really interested in buying one, but am curious to know whether AVX works properly.

On HWBOT, an overclocked retail (oops, not retail, see pics) 6700t scores lower than a 6700k at the same clock speed, because retail non-k processors have AVX crippled with FSB overclocking.

 

EDIT: Nevermind, the results on HWBOT are from engineering samples anyways. Looks like AVX performance gets crippled if you FSB OC these too, so keep that in mind if you're thinking of grabbing one.

[maxgry]

On 13/04/2016 at 6:33 PM, crystal6tak said:

Very nice find! Does Taobao ship world wide or something? That's insanely good performance to price ratio.

U can buy them on aliexpress as well. 

Bryan from tech (yes) city made a video to this CPU last week or so.

 

 

[Dvorskilo]

Does anyone here have a recommended motherboard for this chip and a link for the bios where i can oc it? 

i plan on buying it but i wana find a mb that will actualy run it and oc it

[Sharif]

22 hours ago, Dvorskilo said:

Does anyone here have a recommended motherboard for this chip and a link for the bios where i can oc it? 

i plan on buying it but i wana find a mb that will actualy run it and oc it

Snoop around here

http://www.overclock.net/t/1599531/skylake-non-k-overclock-on-es/490#post_25950476