Take this with a pinch of salt for the time being, but interesting as it appears these new chips are indeed a new revision.
The Stilt @ xtremesystems.org | 2nd September 2014 said:
SourceThe Stilt @ xtremesystems.org | 2nd September 2014 said:So it is finally the second of September...
So far I have posted a picture of a crown (which once belonged king George XII of Georgia) and hashtags #kg & #Alphabet...
#kg which stands for Kilogram
#Alphabet... "Kilo" stands for "K" in the phonetic alphabet
So what is this all about?
Everything below is highly unofficial of course as is everything else I write here.
Piledriver module based Vishera die has been mass-produced in two different die revisions since the prototyping phase.
While all of the revisions have the same major die version (OR-C0), the minor revision has changed.
Initially the first mass-produced die revision was "India" (OR-C0i, prototype and ES only), the second revision was and still is "Juliett" (OR-C0j, retail) and now finally...
The "Kilo" revision (OR-C0k) a.k.a "King Vishera" a.k.a "Vishera Type-K" has arrived.
The "King Vishera" is initially only available in the new models, FX-8370E & FX-8370.
This is most likely the case with FX-8320E also, however I have not been able to test one of them personally.
The new version is likely to be phased-in at least in the other high-end models such as FX-9590 and at some point in all of the remaining models also.
The alledged metal tapeout of the new revision (alledgedly) occured in the beginning of July. So the only way to get a newer revision part is to get one of the new models, atleast in the beginning.
The differences?
- On average 18% less leakage*1 (0-38%) for FX-8370
- On average 53% less leakage*1 (14-106%) for FX-8370E
- Up to 300MHz higher overclocking margin *12
- 100mV less voltage required for the same clocks on average *1
*1 - Compared to an average FX-8320 or FX-8350 CPU
*2 - When not restricted by the cooling or the motherboard (VRM)
The E-version is the best choice for air or water cooling thanks to the ultra low leakage characteristics.
The non E-version does the same clocks however it might require use of a higher end motherboard (with better VRM) and high-performance cooling.
The non E-version has significantly better overclockability under sub-zero temperatures (phase, LN2) since the leakage levels of the E-version are too low for the purpose.
Having an ultra low leakage characteristics is great under normal conditions however under sub-zero temperatures the voltage requirements become a issue.
Basically the low leakage part exhaust the usable range of supply voltage prior reaching it's maximum frequency.
Based on my own tests, I would estimate that >95% of FX-8370 & FX-8370E parts will reach 4.8GHz frequency in 24/7 without a custom watercooling or a ultra high-end motherboard being a requirement.
As long as the temperature (see below) stays =<65 degree C or 149 degree F and the motherboard has even remotely a sufficient VRM you'll be fine.
On a high-end motherboard and a custom watercooling 5.0G - 5.2GHz+ should be doable in 24/7 use with a good specimen.
These chips still draws a vast amount of power when overclocked so the final overclocking potential is basically just the matter of cooling.
The maximum recommended temperature during the worst case stress is 65?C tCase.
Officially the maximum tCase temperature for the various FX models is specified to:
Infra A - FR (125W TDP) - 61.1 degree C
Infra B - WM (95W TDP) - 70.5 degree C
Infra C - OL (65W TDP) - 70.3 degree C
Infra D - HO (45W TDP) - 69.1 degree C
Infra E - SJ (25W TDP) - 70.0 degree C
Infra F - FH (220W TDP) - 57.0 degree C
The tCase temperature must not be mixed with the tCTL control value sometimes dubbed as the "package temperature".
The tCase temperature is also calculated and it represents the simulated case temperature, measured from the very center of the heatspreader (see the illustration).
Neither tCase or tCTL is the actual die temperature. The actual die temperature information is not directly available on these processors. The actual die temperature is significantly higher
than the tCase or the tCTL control value indicates.
The maximum tCTL control value on all of the FX-series processors is 70 units.
When that value is reached the processor HTC logic engages and starts to reduce the power consumption and dissipation by throttling.
Some of the motherboard manufacturers (such as ASUS) alter the limit manually to reduce the chance for throttling.
So when you are talking about the temperature always use the tCase temperature instead of the tCTL control value.
Here is the examples of the wrong and right values in various monitoring softwares.
Red = Wrong (tCTL)
Green = Right (tCase)
The AOD picture also explains the value dubbed as "Thermal Margin".
Also here is a reminder why Prime95 should not be used as a reference for stability when overclocked. It results significantly higher power draw and emitted thermal than any of the most stressful real world applications.If you still find it absolutely necessary to use Prime95 for stability testing please do it this way:
Run it on only two compute units at once (set the thread count to 4 and affinity accordingly) and decrease the cooling to simulate higher power dissipation.
Only the relative Stock or OC results are comparable.
Last edited:
