Example test code fails with "Read wrong data"

[sorvad]

Hi, just loaded up the library and test code. The test fails with "Read wrong data". Rather than use the Hashing of the address I also hard wired a value to write and then test read back but the result was the same. Not sure what's going on, I'm new to FPGA, but could some boards have a different SDRAM? With the GOWIN official example it works, although that only tests one byte at address 0.

[edanuff]

It is failing for me with one Nano 9K but working on another. Very strange.

EDIT: If I drop the frequency down to 51Mhz, it works on the Nano that was failing

[sorvad]

I might have another 9k knocking about. I'll see if I have and test also with that. Ahh... Just seen your edit, that's interesting. The parts may be marginal, perhaps to keep costs down the memory may be factory rejects not making exact spec but OK in most situations? Thanks for your input. I'll try reducing speed.

[svofski]

My part works well at 72MHz. Not at 81.