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post #1091 of 4249 (permalink) Old 11-18-2017, 03:46 PM
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Sure dude. I got nothing else to do tonight.
But for now, not delidded. Kraken x61. Kryonaut paste. But I'll get those numbers. I'll have to use an infared thermal gun thingy to get temps to go along with whatever hwinfo reports. I'll use my kill-a-watt too... Yah. Good idea.

8700k
(10 items)
CPU
Intel Core i7 8700k
Motherboard
Gigabyte Z370 AORUS Gaming 7
GPU
EVGA GeForce GTX 1080 Ti 11GB FTW3 GAMING iCX
RAM
Corsair Vengeance LPX 32GB CMK32GX4M4A2666C15
Hard Drive
SanDisk Ultra II 480GB 2.5"
Hard Drive
PNY CS1311 960GB 2.5"
Power Supply
SeaSonic PRIME Titanium 850W 80+ Titanium Certified Fully-Modular ATX Power Supply
Cooling
Noctua NH-D15
Case
Fractal Design Define S ATX Mid Tower Case
Operating System
Windows 10 Pro
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post #1092 of 4249 (permalink) Old 11-18-2017, 10:03 PM
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IMO most current Z370 boards are under spec'd for OC'd 8700K AVX2 loads.

I'm currently running 5.2Ghz @ 1.33-1.34v load with AVX offset of 2. Prime95 AVX2 blend tests: 220w on large FFT and 280-290w small FFT measured from the wall, delidded CPU hits ~80C max /w D15.

My rig only has a GTX 1070 connected and I'm using a Seasonic Prime Titanium 750w so that 290w wall measurement is around ~250w CPU draw after conversion losses & gpu/mobo/ram overhead.

250w CPU draw @ 1.33v is roughly 188 amps of current, divided by 8 phases = 24a per phase.
The VRMs on my GB Gaming 7 is hitting 101c during small FFT tests even though I'm on an open bench with an 80mm fan blowing over the top set of VRMs.
These fets are supposed to be rated for 60A max and even at less than half of that output, they're hitting over 100C.

I don't see how mid range boards will be able to handle 250w of CPU load.

Of course, if not running AVX2 loads then an OC'd 8700K will probably only hit ~180w max which should be ok for all boards. I do wish GB will release a Z370 Gaming 9 like the Z270 which had 16 phases.

Does anyone know what the max rated current is per VCC socket pin? According to this review: https://www.bit-tech.net/reviews/tech/cpus/intel-core-i7-8700k-coffee-lake-and-z370-chipset-review/1/ the z370 socket has 146 VCC power pins, which means each pin has to carry ~1.28A of current when max loaded @ 188A.
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post #1093 of 4249 (permalink) Old 11-18-2017, 11:55 PM
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Could someone please clarify something for me? I've already bought a locked, non-K i7-8700 (65W TDP) and still haven't decided what motherboard to pair it with. Should I be concerned about the issues (i.e. VRMs' overheating, fewer power phases etc.) of the entry level mobos mentioned in this specific thread or does this only apply to people who are looking to overclock their Coffee Lake CPUs?
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post #1094 of 4249 (permalink) Old 11-19-2017, 12:48 AM
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Nope. Just get a mobo that supports MCE and boost all cores to 4.6GHz or w/e the max is.

Asus 970 Pro Gaming Aura * [email protected] * G1 GTX970 * 2x4GB HyperX 1866MHz DDR3 @ 2220MHz
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post #1095 of 4249 (permalink) Old 11-19-2017, 03:34 AM
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I thought MCE had no effect on locked chips.
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post #1096 of 4249 (permalink) Old 11-19-2017, 05:04 AM
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Well, it only has a point on locked chips, as it boosts all cores to max turbo if set in BIOS. Maybe it was made for something different but that's the only usage now.

Asus 970 Pro Gaming Aura * [email protected] * G1 GTX970 * 2x4GB HyperX 1866MHz DDR3 @ 2220MHz
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post #1097 of 4249 (permalink) Old 11-19-2017, 05:52 AM
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Hello, I am looking at getting a 8700k, delidding and bringing it to 5.2ghz+ on a itx board under water. I am looking at pairing with either a strix z370i with the ek monoblock or asrock fatal1ty z370 itx and a cpu block since the asrock does not have a monoblock. Which one of these two options would give me the highest chance of getting a 5.2ghz+? Or is there any other itx option I can consider
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post #1098 of 4249 (permalink) Old 11-19-2017, 07:47 AM
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Quote:
Originally Posted by drg0ku View Post

Hello, I am looking at getting a 8700k, delidding and bringing it to 5.2ghz+ on a itx board under water. I am looking at pairing with either a strix z370i with the ek monoblock or asrock fatal1ty z370 itx and a cpu block since the asrock does not have a monoblock. Which one of these two options would give me the highest chance of getting a 5.2ghz+? Or is there any other itx option I can consider

I think the broad conclusion is the Strix aren't all that great.
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post #1099 of 4249 (permalink) Old 11-19-2017, 08:03 AM
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I think the broad conclusion is the Strix aren't all that great.

What a shame that asrock itx don't have any monoblock in the market.
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post #1100 of 4249 (permalink) Old 11-19-2017, 10:04 AM
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@ HKPolice,
Midrange boards should top out at around 90-100 degrees VRM with AVX at 1.35V or so (not small FFTs) with case cooling , peak power output roughly 250W at the wall. AIO Coolers or high end air with 250-300W+ peak TDP potential are required to extract ~200-220W continuous out of CPU because you need to account for thermal resistance of thermal paste + liquid metal (Coffee Lake is not a soldered CPU).

https://overclock3d.net/reviews/cpu_mainboard/gigabyte_z370_aorus_ultra_gaming_review/14 --- OCCT AVX , RM1000i ~ 92% efficient
http://playwares.com/pcreview/55679055# --- Prime95 AVX large FFT

Both the ROG Hero and Gaming 7 have been shown running 5GHz 1.4V (Aviutl+x264) with no extra cooling at 90-100 degrees over on livedoor (blog.livedoor.jp/wisteriear/ ).
http://blog.livedoor.jp/wisteriear/archives/1068298475.html
http://blog.livedoor.jp/wisteriear/archives/1068332298.html

What you're seeing is largely a VRM heatsink limitation. That's why to fully utilize the potential of Gaming 7 , ROG Apex/Code/Hero, Taichi, Godlike , etc you would need to cool the VRM with a monoblock or better surface area VRM heatsink than the RGB monstrosity on the Gaming 7.
At least one user reported VRM temperature drops on the Gaming 7 from switching thermal pads and torquing down the VRM heatsink more.

With boards such as GBT Gaming 5 (4.1 and 5.3 °C/W thermal resistance junction to case), MSI's M5 (3.8 and 5.3 °C/W thermal resistance mosfet junction to case), Asus Z370-A Onsemi variant (4.1 and 4.9 °C/W junction to case), Asus E/F/G Strix boards (worse for monoblock purposes due to 25A package limit ; 4°C/W thermal resistance junction to case) getting a monoblock won't increase your potential very much since you're mosfet package limited to an extent. You're looking at about 20-30A maximum per phase without adjusting RDS(on) for voltage and temperature (+20-30% difference at between 80 to 100°C). The STRIX E/F/G just happen to have lower max current for the low side fet (25A package limit).

If you're thinking of watercooling a midrange board (not really worthwhile IMO), a GBT Gaming 5 is a far better bet. Firstly, all components for doubling/dual driver are on the front of the board (under the VRM heatsink area). Secondly, it has been shown to run cooler even without watercooling. Thirdly, the mosfets can handle much more current if kept cool (it's the same power design as on Z270X UD5) to the tune of 45A at 25°C mosfet case temperature for the high side 4C10N and 69A for the low side 4c06N.

The MSI M5 and Pro Carbon are decent but you must keep in mind that the dual drivers (up1962) are on the back of the board. The 4C029 has a similar 46A at 25°C mosfet case temp so there's no major advantage in that respect.

The moment there is a VRM block for the Asrock Z370 K6 or Extreme4 , those would be even better than the GBT Gaming 5. The Fairchild variant (dual channel mosfet) can handle 56A at 25°C on the high side channel and 84A at 25°C on the low side. The Sinopower variant can handle 73A at 25°C for the high side channel and 186A for the low side channel. The main reason why you would prefer the Fairchild variant is that it has faster switching times. With the Asrock Z370 K6/ Extreme4 you're more limited by the CPU power connector than the board.

edit: I did the math with the Fairchild and Sinopower on 5 phases in dual driver mode vs the 10 discrete drivers on the Taichi, you'd still come out ahead of a ONsemi/Vishay 8 phase solution using the mosfets on the GBT Gaming 5 / MSI M5 even if they were interleaved. It is partially due to the approximately 2x lower RDS(on) of the low side channel but also due to lower switch times on the high side channel. Of course in reality the STRIX E/F/G, GBT Gaming 5, MSI M5 may not be interleaved.
Quote:
Originally Posted by cortis View Post

Could someone please clarify something for me? I've already bought a locked, non-K i7-8700 (65W TDP) and still haven't decided what motherboard to pair it with. Should I be concerned about the issues (i.e. VRMs' overheating, fewer power phases etc.) of the entry level mobos mentioned in this specific thread or does this only apply to people who are looking to overclock their Coffee Lake CPUs?

A stock i7-8700k draws about 100W in Handbrake with x265 (AVX2) and about 120-130W hammering it in Prime95 with AVX. The i7-8700 is likely going to avoid turboing as high as the i7-8700k for AVX loads.
(refer to ATX12VV power draw http://www.hardware.fr/articles/970-3/overclocking-pratique.html)

This thread mainly applies to overclocked, delidded CPUs on AVX or continuous loads with AVX. For your use case, an Asus TUF / Z370-P, Asrock Killer SLI, MSI Tomahawk & lower, or Asrock Pro4 are still not great ideas due to cut down USB gen 2 , features (such as wifi, M.2 slots), and/or audio. The Gigabyte Gaming 3 , K3 , XP SLI & HD3P then become stronger contenders due to Dual BIOS but the MSI SLI PLUS is usually cheaper. The STRIX-H is still terrible since it costs quite a bit for what it is.

If you buy a cheaper board and use it with AVX on stock CPU, the sustained all core turbo will not hit power limits unless LLC is at ridiculous levels.
Quote:
Originally Posted by drg0ku View Post

Hello, I am looking at getting a 8700k, delidding and bringing it to 5.2ghz+ on a itx board under water. I am looking at pairing with either a strix z370i with the ek monoblock or asrock fatal1ty z370 itx and a cpu block since the asrock does not have a monoblock. Which one of these two options would give me the highest chance of getting a 5.2ghz+? Or is there any other itx option I can consider

I would limit your expectations for an ITX board.

For Fatal1ty ITX , you could probably use the Koolance VRM blocks.
https://www.amazon.com/Koolance-MVR-100-Water-Block-Motherboard/dp/B004YF8CCA/
https://www.amazon.com/Koolance-MVR-40-Water-Block-Motherboard/dp/B004YF8NWO , http://www.performance-pcs.com/koolance-mvr-40-mb-vreg-no-nozzles.html

Or trim to fit https://modmymods.com/watercool-heatkiller-microsw-x-40-diy.html , http://www.aquatuning.us/water-cooling/gpu-water-blocks/gpu-vrm-cooler/14785/watercool-heatkiller-microsw-x-40-diy , http://www.performance-pcs.com/watercool-heatkiller-microsw-x-60-diy.html , https://modmymods.com/watercool-heatkiller-sw-x-60-diy-lt.html

I personally wouldn't buy the STRIX-I because even if you put it under water you're limited to about 14.5-20A per 4C86N mosfet (package limit is 20A) x 6 phases means safety is around 150W tops. The Fatal1ty ITX is far more capable due to the 5 phase power design using 60A Intersil smart powerstages along with the heatpiped heatsink.

The way I see it , for monoblocks and VRM blocks you should only buy a board with mosfets that have a higher package current limit because otherwise you're still limited by the mosfets innate package limits.

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