It seems DDR-2600+ is very much doable for benching, even with an 'average' IMC and air cooling.
The timings need to be heavily recalibrated thou... and none of the most popular motherboards have these adjustments available in bios.
I have requested these to be added, however none of the vendors have reacted in any way (as usual).

Fortunately I am making a small tool (TCI K˛ Loader) which will latch these timings so that you can boot into Windows without crashing
No user interaction required, the system only needs to be able to post and you will need to have a spare USB-stick.

Testing the actual stability of overclocked memory on Trinity is the funny part (not really).
With memory testing tools (such as Memtest86/+, HCI Memtest, R.S.T, Linpack, Prime95 Blend, etc) you will only be able to tell if the actual DRAM modules are failing. This tells nothing about the actual stability (CNB/IMC). These tests will not catch the CNB/IMC related errors unless it is absolutely melting down.

Since the GNB and CNB/IMC are a single unit (UNB), stressing GNB will also stress the CNB/IMC.
Just like on Llano the ultimate stability test for overclocked memory (and / or CNB) is 3DMark06 GT-1 (Return to Proxycon).
DRAM module related unstability is immediately visible as artifacts and any unstability in IMC/CNB will halt or crash the program (/system) usually within the first 20 seconds of the test. If the system passes 10 loops of GT-1 it will never crash in any other 3D app either.