My CPU refuses to utilise more than 75% (2.8ghz) and i can't figure out why

[alexbe]

I trust there are knights in shining armour with the expertise I'm lacking that would be able to tell me where I am going wrong. I'm very grateful to anyone who takes the time to read through this and I would really appreciate any advice at all.

So, I played with my BIOS settings for 2 days, and could not find a combination that would consistently keep all four CPU cores at 100% while under stress tests. I tried overclocking with and without turbo boost. I played with LLC, Cool&Quiet, C6, APM. I tried hundreds of combinations and ran tests. I made slight changes to Vcore, though never exceeding 1.440v, and kept my CPU clock at 3.8ghz. I don't think the power throttling is not due to heat, as my CPU never exceeds 45C.

My Specs:
CPU: AMD A8 7670k 3.6ghz (up to 3.9ghz)
Mobo: Gigabyte GA-F2A68HM-DS2
CPU Cooler: CoolerMaster Hyper 212x
GPU: Radeon RX 470
RAM: 2 x 8gb Crucial 1600mhz
PSU: Corsair CS850M 850W 80+ Gold

My BIOS setup:
CPU Clock Control: 100.00mhz
Processor Graphics Clock: 757mhz - Default
CPU NB Frequency: 1800mhz - Default
CPU Clock Ratio: 38
CPU Frequency: 3.8ghz

Turbo Perfomance Boost: Disabled
AMD Cool&Quiet: Disabled
cTDP function: Disabled - Default
SVM Mode: Enabled - Default
C6 Mode: Disabled
APM: Disabled

CPU Vcore: +0.096
NB Core: Normal - Default was Auto
DRAM Voltage: Normal - Default was Auto
Vcore LLC: Medium
NBVID LLC: Medium

Using Prime95 for stress test, HWMonitor to watch Vcore, AMD Overdrive to monitor temps and Resource Monitor to watch CPU frequency. I've identified 2 scenarios through testing:

1. My BIOS Setup with Cool&Quiet Enabled
For 30 seconds CPU runs at 3.8ghz --> All four cores at 99-100% usage and Vcore at 1.404
CPU begins to throttle, all cores fluctuate simultaneously between 65% and 78% (approx. 2.8ghz) Vcore drops to 1.368v or less

2. My BIOS Setup + Cool&Quiet Disabled
CPU consistently runs at 75% capacity, frequency and Vcore does not fluctuate (2.8ghz and 1.404v)
CPU cores 0 and 1 display 100% usage while CPU cores 2 and 3 display 50% usage

Summary:
Both scenarios yield only 75% CPU usage (2.8ghz) or less while under a stress test. Regardless of settings, I cannot attain a consistent 100% CPU usage on all four cores.

I don't mind if I need to give up on overclocking but I just want my CPU to run at 100% capacity. There are certain games I should be running at Very High settings but can only run at Medium-Low settings due to this throttling.

Again, thank you to anyone who read through this, any help is appreciated! Alex.

 

[urbancamper]

In the bios put AVX on auto if it isn't already. During stress testing use prime95version26.6 small fft testing only. If your also testing AVX it will lower your clock speed.