Minecraft 1.7.10 / Forge 1208 / Compact Machines 1.7.10-1.6
EnderIO-1.7.10-2.1.0_beta.36 ("RF Only" Dev Branch)
Mekanism 1.7.10-7.1.0.92

Let me explain the issue within the context of the above picture.

I am using 2 Creative Capacitor Banks from Ender IO, both of which have a 5 Million RF/t maximum transfer rate. The top Compact Machine block is connected via Tier 3 power conduit from Ender IO, which has a maximum transfer rate of 20k RF/t. The bottom Compact Machine block is connected via Ultimate Energy Cable from Mekanism, which has a maximum transfer rate of 12.8k RF/t.

If I go into the top Compact Machine, I only get 80 RF/t of actual power flow from the machine interface on the corresponding powered wall. This is a total of 80 RF/t to anything and everything.. not 80 RF/t per machine. If I get the Compact Machine block and place it directly adjacent to the Creative Capacitor Bank block, I still get a maximum power transfer rate of 80 RF/t on the inside.

If I go into the bottom machine.. nothing actually receives power. Externally I have tested and the Ultimate Energy Cable is actually pulling power from the creative energy cell, as I can charge Mek Energy Cubes off it. Unfortunately however none of that power is getting into the interior of the machine block.

Ender IO and Mekanism will behave just fine when interacting with each other.. no strange numbers. It's only when interacting with Compact Machine is it that I start seeing this odd behavior.

Help?

I cannot reproduce the bottom machine at all. But looking at your picture, the capacitor does not even output into the cable, i.e. this is not related to compact machines (try placing an universal cable beside a capacitor with the output configured - it should fill up with green stuff ;) )

I could reproduce the top one to a certain degree - never got down to 80 rf/t, but rather the expected 500 RF/t (Buffer has 10000 RF, every 20 ticks the buffer gets fully transferred, hence 500 RF/t). Anyway, i have added a config option that allows you to tweak this setting - and also changed the default to 0, i.e. it should behave like a cable able to transfer 10000 RF/t. If you need more, use more sides ;)

Please try and see if Compact Machines v1.7 works better for you in regards to RF throughput.

With this recent commit you can import/export directly to Mekanism cables.
@aidancbrady Is there a specific reason you are always returning 0 when simulate is set to true in https://github.com/aidancbrady/Mekanism/blob/master/src/main/java/mekanism/common/multipart/PartUniversalCable.java#L272 ?
I figured this is a way to pre-check whether energy transfer would have any effect and to skip it if it does not. Hence my previous code checked via simulate first - since your receiveEnergy always returned 0 for it, power did not flow into the cables.
Doesn't this prevent other mods from interacting with the universal cables as well? Or am I not supposed to simulate energy transfers beforehand?
Any inside would be appreciated, thanks.