Larger cache will reduce access time assuming data has been cached.
If it is not in the cache, then the cache needs to be flushed which takes a little bit of time for new data to be written to the cache. The more cache, the more time it takes to flush and write new data.
Therefore, it is a "catch 22", if the data is in the cache, then you lucky and access time is low. If the data is not in the cache, then access time can be relatively high.
Large cache is mostly useless; the RAM is 4GB and that caches alot more than the tiny xMB cache on HDDs; Windows won't request a recently requested block if that block is already in RAM.
HDDs need a cache for write buffering; more doesn't really mean better in that regard. The 4K sector disks use 64MB cache, which helps them to avoid reading when they have to write small chunks. By using the cache they may skip the slow read-modify-write cycles that these 4K sector disks do in order to emulate 4KiB sectors.