RAM timings actually don't do much. they're measured in clock cycles
you have your frequency, which is how many clock cycles it runs at per second.
normally it is 200MHZ or 200,000,000 HZ
that means 1 clock cycle at normal speed takes 1/200,000,000 seconds, or 0.000000005 seconds. not a lot is it. you can blink, and millions of clock cycles can go by in that time.
I would recommend increasing the timings and see if you can push up the HTT