Technically the H210 supports up to a 325mm GPU, but this does not consider any radiators/fans installed to the front of the case. Therefore, if you plan on installing a liquid cooler to your H210 build or plan to include fans in the front of the case, you will need to subtract the width of the fans and radiator from the clearance available in this case. For example, the Kraken X53 has a 30mm thick radiator, and the included AER P fans are 26mm thick. You would then subtract 56mm from the 325mm of clearance we'd typically have to give us 269mm of GPU clearance.
Please also keep in mind that there is a 44mm max clearance for the thickness of the GPU. Unfortunately, GPUs thicker than 44mm will not fit.