When we tested if the memory timings interfered on computer performance, using a high-end video card, we concluded that there was no practical performance change between using high latency or low latency memories.
However, when we tested the impact of dual-channel memory configuration on gaming performance using a high-end video card, we also did not notice any improvement; but while using integrated video, the result was very different, and we noticed a fair performance improvement.
Because of this, we decided to test if the memory timings could impact the integrated GPU performance, and the result was clear: yes, there is a performance improvement. However, it is actually small, about 5% in most cases.
So, if you are building a computer with integrated video (specifically using an AMD APU, which was the processor we used), and you have the option to buy memory modules with lower latencies for a small difference in price, go ahead. However, if the difference of price between “normal” and low latency memories if significant, forget about it: there are another parts where the investment brings a bigger performance improvement.