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Journeyman III

Real clock of ram is low and fsb:dram is async

I bought a new asus fx505du with cpu ryzen 7 3750h, 8gb of ram 2666mhz and gtx 1660ti. I've just found that in task manager showed that my ram just work in 2400mhz, and when i tested it with cpu z, 3dmark the speed of my ram is only 1866mhz and the ratio fsb:dram is async. I'd tested some other apps and they show it's 2400mhz but i think that cpu z and 3d mark are two apps i can trust more. Anyone has a problem like me? Help me please! I think it's a problem from the mainboard or the cpu...

2 Replies
Journeyman III

Same Problem here. Bought a ASUS TUF FX505DV with AMD Ryzen 3750H with RTX2060, it has 2x8GB DDR4 Micron 2666Mhz installed and CPU-z shows FSB:DRAM async.

Dont know why, may ASUS normally build Intel systems so they don't specifically buy 2400Mhz RAM for AMD setups.

But as you can read on Wikipedia front side bus you see an entry "overall system performance can vary in unexpected ways with different FSB-to-memory ratios".

So i decidet for my personal solution to buy a new pair of RAM, now that they are so cheap anyway, 2x16GB 2400Mhz to bring the FSB:DRAM Ratio synchron.

May there are other solutions with BIOS settings?

Hope i could help you a bit.

By the way, thanks to AMD, the Ryzen 7 have good performance. I am positively surprised!


Checked for your CPU specs it support upto 2400Mhz so its possible (just like my 505DT) they used a 2666 and under clocked it to 2400