nTune is a funny beast. It's a huge piece of software that works its way through every part of your Nvidia motherboard, working on the speed of the buses, the CPU and, if you have it installed, your SLI memory. The strange thing is that it starts by overclocking the PCIe bus, in this case from 2500MHz to 3950MHz. Then it sets to work on the FSB, which it typically raised from from 1066MHz to 1140MHz to give a CPU speed of 2.85GHz. After that, nTune tightened the memory timings and then it overclocked our graphics card by a consistent ten per cent.
Longer bars are better
Using the nTune 20-minute coarse tune, the 680i SLI wouldn't overclock at all and the LT managed a trivial rise in performance. When we tried to manually overclock the CPU in both cases it refused to run any faster, however we have to make it clear that we left all voltages standard.
Longer bars are better
On these settings the LT wouldn't complete a benchmark test, so we pulled the PCIe speed back to 3250MHz in one big step. The LT was then stable, but hardly any faster than standard. This was very disappointing and it made us take a good long look at the marketing that accompanies 680i LT SLI. Clearly it's intended to deliver most of the benefit of the 680i SLI, including nTune 5, but at a lower price. To our mind nTune has masses of potential, but doesn't deliver anything that you can't get from the BIOS of a decent motherboard from any one of six or more manufacturers.
We did, we just kept the results to ourselves as they were a bit dull
We tried a quick and dirty manual overclock of the FSB with both EVGA boards and got nowhere which is a bit grim when both the Abit 650i SLI and Asus 680i SLI yielded an easy overclock.
Also, the performance charts were already plenty confused so adding any more lines seemed like a bad idea.
A few extra points:
1- I (that's Leo rather than The Reg) won't entertain overclocking unless it is 100percent stable and reliable with a minimal risk of fritzing hardware, so I stay clear of voltage changes if humanly possible.
2- The 680i LT has very little in its favour if you discount nTune. I feel that the test results show that you CAN discount nTune in which case you can forget about the LT and plump for a 650i SLI.
3- Perhaps it's coincidence but if you go here
there's no 'further information' on the 650i SLI
buy now while stocks last
Excellent review, though for the reference boards why didn't you try a manual overclock aswell as the ntune?
Ntune is pants at overclocking.