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Intel Skylake / Kaby Lake

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TheF34RChannel

Senior member
May 18, 2017
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Tiny Tom Logan said:
Let's get the awkward bit out of the way first. Yes we were hoping to bring you a review of both the eight core i7-7820X and the ten core i9-7900X today, but for reasons best known to themselves Intel withheld samples from everyone because a couple of sites broke NDA last time. So we're sans samples and other sites - mentioning no names, let's call them Gexus - broke NDA anyway. If I was Intel's lawyers I'd be expecting some work in the coming days. All of which doesn't overcome the fact that we just have the i7-7820X to show you today.

There we have it, the i7-7820X. As fast as you expect it to be, but at £599 not nearly as expensive as Intel might have made it. Award? We're not giving it one. Why? It would be unfair to award a processor we had to source ourselves just so that we had some content live on NDA. We were promised a 4c8t and a 10c20t but apparently all of the (legit Intel) samples are delayed and thats why we have the 8core 7820X, we were trying to make sure we filled in the gaps and brought you the most thorough launch day review we could for all of our readers. At least we didnt break NDA though......

Just as a parting gift, if youve read this far and youve watched the video thank you, if youre here to see if you need to buy the 7820X or for that matter any X299 as the basis for your gaming system we have one thing to say to you. Don't. In the grand scheme of things you either want to go and grab a Z270 /7700K based system or if you want a few more cores for occasional rendering and streaming then just go buy the Ryzen 1700. If you do buy AMD though don't turn into one of the mentalist fanboy keyboard warriors ruining the scene at the moment.
Review: https://www.overclock3d.net/reviews/cpu_mainboard/intel_core_i7_7820x_skylake_x_review/1
 

Bouowmx

Golden Member
Nov 13, 2016
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AVX-512 rates, from Anandtech:
Ian Cutress said:
The six-core and eight-core Skylake-X parts support one fused FMA for AVX-512-F, although the 10-core will support dual 512-bit AVX-512-F ports, which seems to be located on port 5. This means that the 10-core i9-7900X can support 64 SP or 32 DP calculations per cycle, whereas the 8-core/6-core parts can support 32 SP or 16 DP per cycle.
Ian Cutress said:
For anyone on the consumer side who wants to play with AVX-512, it is worth reiterating that there is a separation between the Skylake-X processors: the 6-core and 8-core parts only support one FMA per core, whereas the 10-core supports two FMAs per core.
So the segmentation goes half-rate in Core i7-7800 series, and standard-rate in Core i9-7900 series.
 

Karnak

Senior member
Jan 5, 2017
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Pushing all of the Core i9-7900X’s cores with Prime95 or LuxRender propels power consumption to incredible heights. You do get 48 percent more rendering performance in LuxRender, but at the expense of 58 percent-higher power use. This approach has the elegance of a sledgehammer. Then again, if you need speed at any cost, Core i9-7900X is top-notch.

http://www.tomshardware.com/reviews/intel-core-i9-7900x-skylake-x,5092-10.html

Your choices come down to high-end all-in-one packages or a custom water-cooling loop. Air cooling is completely out of the question if you expect the -7900X to run comfortably under full load.
http://www.tomshardware.com/reviews/intel-core-i9-7900x-skylake-x,5092-11.html
 

pantsaregood

Senior member
Feb 13, 2011
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Should run fine on high end air coolers if it works on AIOs. Every HEDT part has claimed to need water cooling, but top end dual tower coolers pretty consistently match or outperform 240mm AIOs and match 280mm AIOs.

That said, we have an eight core CPU hitting 5.0 GHz without being delidded. Looks like these are running on 14nm+, which means we could see binned/delidded CPUs hitting 5.2/5.3 GHz.
 

vissarix

Senior member
Jun 12, 2015
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Damn that 14nm+ process is incredible...it allows huge overclock headroom...i can only wonder what Coffeelake will clock like at this point...maybe 5ghz+ easily since it is on an improved 14nm++...

btw Skylake X 8cores running at 5ghz are just amazing:p
 
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coercitiv

Diamond Member
Jan 24, 2014
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First I saw the Prime95 power numbers and I didn't mind it much, it's Prime95 after all, and gaming power consumption was ok. But then I saw this:


That's a bit much.
 

krumme

Diamond Member
Oct 9, 2009
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Should run fine on high end air coolers if it works on AIOs. Every HEDT part has claimed to need water cooling, but top end dual tower coolers pretty consistently match or outperform 240mm AIOs and match 280mm AIOs.

That said, we have an eight core CPU hitting 5.0 GHz without being delidded. Looks like these are running on 14nm+, which means we could see binned/delidded CPUs hitting 5.2/5.3 GHz.
Dont you think its a stretch? Thg:

"All-in-ones like Corsair's H100i and Enermax's LiqTech 240 hit their limits at stock frequencies under Prime95. The custom loop threw in the towel at 4.6 GHz."

"A Tcore of up to 65°C and a heat spreader temperature of approximately 24°C make for a difference of more than 40°C. That's at 230W. Once the 300W line is crossed, even the Alphacool Eiszeit Chiller 2000 taps out. This isn’t even difficult to do: with a Core i9-7900X running at 4.6 or 4.7 GHz, using the voltages needed to get there, even simple rendering applications trigger those levels. The highest power consumption numbers we saw were just north of 300W, which had the CPU hitting its 100°C thermal limit consistently. An emergency shutdown followed soon after."
 
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raghu78

Diamond Member
Aug 23, 2012
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The 7800x and 7820x seem to be the best Skylake-X SKUs in terms of perf/$. Its good to see value in the HEDT space after a long time. Skylake-X SKUs like 7800x and 7820x are more attractive than Ryzen 7 SKUs due to higher IPC, higher max clocks and more consistent performance across a range of workloads. btw it looks like Skylake-X would have benefited from 14++ but given the long development cycles of these CPUs, 14++ was not available at the time. This means Cascade Lake-X in 2018 should do much better in terms of power consumption.
 
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R0H1T

Platinum Member
Jan 12, 2013
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Dont you think its a stretch? Thg:

"All-in-ones like Corsair's H100i and Enermax's LiqTech 240 hit their limits at stock frequencies under Prime95. The custom loop threw in the towel at 4.6 GHz."

"A Tcore of up to 65°C and a heat spreader temperature of approximately 24°C make for a difference of more than 40°C. That's at 230W. Once the 300W line is crossed, even the Alphacool Eiszeit Chiller 2000 taps out. This isn’t even difficult to do: with a Core i9-7900X running at 4.6 or 4.7 GHz, using the voltages needed to get there, even simple rendering applications trigger those levels. The highest power consumption numbers we saw were just north of 300W, which had the CPU hitting its 100°C thermal limit consistently. An emergency shutdown followed soon after."
Anyone saying OC on Skylake-X is a piece of cake is doing free PR for Intel, that or brand loyalty, solder would've been much better even when running it on stock clocks.
 

krumme

Diamond Member
Oct 9, 2009
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This has me very upset.
Why? Dont know your need. Cant you code for it anyway? I mean thats a plus.

As AT said the tim is suitable for up to 7700k. Unless you delid it seems to me most is temp limited anyway on stock for the 7900x on standard water. Its segmentation but imo it doesnt hurt like it could have done with a soldered solution.
 

krumme

Diamond Member
Oct 9, 2009
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The 7800x and 7820x seem to be the best Skylake-X SKUs in terms of perf/$. Its good to see value in the HEDT space after a long time. Skylake-X SKUs like 7800x and 7820x are more attractive than Ryzen 7 SKUs due to higher IPC, higher max clocks and more consistent performance across a range of workloads. btw it looks like Skylake-X would have benefited from 14++ but given the long development cycles of these CPUs, 14++ was not available at the time. This means Cascade Lake-X in 2018 should do much better in terms of power consumption.
Agree. 7800 and 7820 is damn fine cpu for a broad variety of loads. An 1700x is still cheaper system cost than 7800 and 1700 shines with crazy efficiency and low price vs those performance dudes, but imo 1800x is now least attractive. The gaming perf is still shaky but lets see how it pans out.
The delid is a letdown. But i take it from the positive side. They seem factory oc to me and power consumption is high so there is a hard temp limit if you want to keep your cpu a 80c. 7820x stock looks nice to me and suitable for high end air coolers like a d15 if you can perhaps accept high temps for rendering.
 

Edrick

Golden Member
Feb 18, 2010
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Why? Dont know your need. Cant you code for it anyway? I mean thats a plus.

As AT said the tim is suitable for up to 7700k. Unless you delid it seems to me most is temp limited anyway on stock for the 7900x on standard water. Its segmentation but imo it doesnt hurt like it could have done with a soldered solution.
Yes I can still code on it (my primary reason for going Skylake-X), but killing port 5 (AVX-512) for the sake of segmentation is just crap. I mean I can see gimping cores, cache and even PCIe lanes to an extent, but now execution ports?
 
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Zucker2k

Golden Member
Feb 15, 2006
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You mean other than CB r15, what other load are you looking for?
Oh shoot! Lol. I need my afternoon nap.

Edit: There's still something wrong with that chart if the 6900K is consuming more than the 6950X.
 
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LTC8K6

Lifer
Mar 10, 2004
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Overall power use is probably not that bad considering that it gets the job done faster and returns to idle sooner.
 
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LTC8K6

Lifer
Mar 10, 2004
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Anyone saying OC on Skylake-X is a piece of cake is doing free PR for Intel, that or brand loyalty, solder would've been much better even when running it on stock clocks.
Hopefully BIOS tweaks will help with the voltages/temps/power.
 
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khon

Golden Member
Jun 8, 2010
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These reviews don't look good for Intel at all. Poor performance in games, worse performance/$ compared to AMD, bad thermal performance, and much higher power consumption.

Who is this for then ? Is there a large market for people who don't play games, don't care about the price and don't care about power consumption ?
 
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coercitiv

Diamond Member
Jan 24, 2014
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This doesn't mean much without knowing what "load" actually means.
It's Cinebench R15 and X299 + 7900X is using around 50% more power than X99 + 6950X for around 16% more performance.

I can't help but feel we could have had quite a bit more performance on Broadwell-E as well if Intel had been just as relaxed on power consumption.

Are you going to run that benchmark all day or something?
You mean a real world renderer is something people don't use?
 

Zucker2k

Golden Member
Feb 15, 2006
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It's Cinebench R15 and X299 + 7900X is using around 50% more power than X99 + 6950X for around 16% more performance.

I can't help but feel we could have had quite a bit more performance on Broadwell-E as well if Intel had been just as relaxed on power consumption.


You mean a real world renderer is something people don't use?
There's something wrong with that graph. Check the 6900K power consumption figure. Still, if the 7900X is really up by that much, then there's something very wrong.
 

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