I assume your reffering to WHDLoad. I mentioned this in a previous thread but I will bring it here as it has me relavence.
Basically I had a similarly specced 600 and found a lot of games simply would not run no matter what. Part of the problem is the amount of RAM you have and another is the CPU.
In an attempt to rectify things I tried the ClassicWB 68k package. This is a very lightweight version of Work Bench that was designed for low specced Amiga's. It also had a cool feature that allowed it to free more memory if the right mouse button was held during boot. Even this failed.
You main options are to get something like the ACA 630/25 Stealth Accelerator and the kick roms to support it. This will run any WHDLoad without issue.
Another option is to replace the Floppy drive with a emulated drive like the HxC. These are cheaper than the expensive accelerators and work just like the real floppy drive would. But your loading the games from an sd card.
If your not taling about WHDLoad then maybe your havving issues with the amount of RAM in the system and some games not been compatible with it. Also if you have the stock Kickstart ROM installed I know a lot of the earlier games simply won't run without something like RELOKICK.
