The cores:
As we can see on the right the 8700K is a larger die compared to the Kaby Lake quad and dual core CPU's as it should be.
This image also confirms that that notches were not moved to prevent accidental insert into the wrong socket, this is the only issue I have with this platform. I heeded the warning from the design engineers @ Intel that pins were moved and do not attempt cross platform CPU testing. I did not want to kill my chip doing something I was told would kill processors. |
Core sizes 6,4,2
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Coffee Lake
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Kaby Lake
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These slides were leaked and show the changes in pin assignments proving that the Kaby Lake and Sky Lake are both incompatible
per core overclocking:
Per core overclocking is not the same as the HEDT parts, there is some limitations to maximum multiplier selection. There is no per core P states and this is how the rules work on Z370 with 8700K CPU.
Without Per Core you set all cores to 49x and all cores run at 49x pretty much what we always do.
To use per core you must enable in BIOS and then you can set the cores in a pattern 1, 2, 2, 1 meaning, set the best core to 50x and the two next cores at 49x, next two cores at 48x, and last core to 47x. Reboot into windows and your cores will now be staggered to what you set. This configuration benefits from setting affinity to the max core on single threaded applications and games. My screen shot shows you can break the rules some, you can go much higher on the first core, second set of cores will be one multiple lower than that and so on. |
The rules are still a bit simple but try my example it works and can test from there.
Real Time memory latency control:
In BIOS there is a setting to enable this feature, by default on Asus and Gigabyte this is disabled. Once enabled the menu option will appear in XTU 6.4.1.8 and higher.
These are the options you now have.
These are the options you now have.
Adjusting these settings do not require a reboot.
Durability:
The PCB is thin like the Kaby Lake and Sky Lake CPU's and can easily bend under too much mounting force. This was an issue originally but overclockers adjusted to compensate to prevent bending, for normal use this is not an issue at all.
I test fired the machine with no heat sink, the machine posted and went into BIOS. I was unable to load into Windows and the machine protected itself and shut off.
As we have seen with previous generations of 14nm processors is a very durable process, these chips do not die easily and can can easily handle up to 1.6v with the AOI.
I test fired the machine with no heat sink, the machine posted and went into BIOS. I was unable to load into Windows and the machine protected itself and shut off.
As we have seen with previous generations of 14nm processors is a very durable process, these chips do not die easily and can can easily handle up to 1.6v with the AOI.
Limits AIO:
The cooling used is an AIO Thermaltake Water 3.0 Ultimate cooler, a really good performance cooler capable of handling the heat load when overclocked beyond 5Ghz and running stress benchmarks.
One of the tests I do is walk up the multiplier and run XTU for a quick stability test while I watch the temperatures. I walk it up to 90C. Both chips were able to run everything at 5.2Ghz and at 5.3Ghz I was starting to throttle on this cooling. I was not running the AC assist, just two 120MM fans. I was at the limits of the AIO and the CPU with this thermal window. The eventual VCore was 1.48v, a bit high but acceptable for 5.2Ghz with AUTO settings.
Backing off the VCore was possible, I was able to bring the vcore down to 1.32v and this did bring my temperature down considerably but I did not allow me to run with stability at 5.3Ghz, 1.4v+ was needed to get into windows @ 5.3Ghz.
I also was very happy with the cache speed of 5Ghz on the AIO with both 8700K chips. I believe the max in the screen shots is 5600Mhz but I ran a few things with some bclk adjustments.
One of the tests I do is walk up the multiplier and run XTU for a quick stability test while I watch the temperatures. I walk it up to 90C. Both chips were able to run everything at 5.2Ghz and at 5.3Ghz I was starting to throttle on this cooling. I was not running the AC assist, just two 120MM fans. I was at the limits of the AIO and the CPU with this thermal window. The eventual VCore was 1.48v, a bit high but acceptable for 5.2Ghz with AUTO settings.
Backing off the VCore was possible, I was able to bring the vcore down to 1.32v and this did bring my temperature down considerably but I did not allow me to run with stability at 5.3Ghz, 1.4v+ was needed to get into windows @ 5.3Ghz.
I also was very happy with the cache speed of 5Ghz on the AIO with both 8700K chips. I believe the max in the screen shots is 5600Mhz but I ran a few things with some bclk adjustments.
LIMITS Cascade:
My Cascade is capable of -120C with a temperature drop of 2C under full load, and capable of beating most recorda set by 7800X easily proving that the Coffee Lake processor line is superior to everything we have seen to date.
On cascade I beat a few 6 core world records, namely XTU where I crushed it by more than 10%. On LN2 the beating will be so horrendous it should be a felony, people will cry about how good Coffee Lake is and that it hurts the HEDT chips.
The 7800X 6 core XTU world record was set on LN2 with max tuning on memory. I used a cascade and primary settings. This is win for us, the consumer. We are getting the best Intel can deliver as quickly as they can deliver it to market. Intel is showing that they can push new technologies quickly although many will argue that releases too quickly hurts investment value of systems only a months old.
Running a few threaded things 6Ghz took tuning on the cascade due to my not being able to push towards -200C, I could not see the full potential of my chips but by the leaks of other early 8700K results, benching near 7Ghz is possible.
On cascade I beat a few 6 core world records, namely XTU where I crushed it by more than 10%. On LN2 the beating will be so horrendous it should be a felony, people will cry about how good Coffee Lake is and that it hurts the HEDT chips.
The 7800X 6 core XTU world record was set on LN2 with max tuning on memory. I used a cascade and primary settings. This is win for us, the consumer. We are getting the best Intel can deliver as quickly as they can deliver it to market. Intel is showing that they can push new technologies quickly although many will argue that releases too quickly hurts investment value of systems only a months old.
Running a few threaded things 6Ghz took tuning on the cascade due to my not being able to push towards -200C, I could not see the full potential of my chips but by the leaks of other early 8700K results, benching near 7Ghz is possible.
TIM performance:
Intel would not confirm or deny the TIM had been changed but by look and taste it seems the same. My non delid part was able to push beyond what my delid part could do. My delid part has Thermal Grizzley applied.
"Hey Charles, we don’t share detail on TIM as performance characteristics of our thermal interface material is considered Intel intellectual property."
So for those who do not delid and not running LN2 it is good to know that the stock TIM can run at 5Ghz or more with good AIO cooling.
Going beyond -120C I am sure a CPU delid with aftermarket TIM will be the only option.
"Hey Charles, we don’t share detail on TIM as performance characteristics of our thermal interface material is considered Intel intellectual property."
So for those who do not delid and not running LN2 it is good to know that the stock TIM can run at 5Ghz or more with good AIO cooling.
Going beyond -120C I am sure a CPU delid with aftermarket TIM will be the only option.
IMC and Cache:
Fantastic! Coffee Lake is pure win.
Intel increased the cache sizes for Coffee Lake!
Intel's best work yet, this team needs a raise.
Intel increased the cache sizes for Coffee Lake!
Intel's best work yet, this team needs a raise.