Weird Lag in Touhou 13

[Sage Ω (Ultima)]

The game used to work fine but now after I play for while the fps gradually decreases and by the time I get to the end of stage 3 it's 20 to 30fps.

But it stays there for the time that the game is running so if I quit and play another stage or practice a spell card the game is still laggy as shit.

I ran the game beside Task Manager and nothing looked out of place besides the game's memory. It was using around 250 -300mb of ram and 30% of the CPU.

If I close the game and open it again the CPU usage barely makes 10% and it's only using 70mb+ ram and as I progress that number increases and the CPU usage increases to the situation I described earlier and like I said this is no normal lag where it happens at specific moments, this lag is permanent until the next time I load up the game. I've tried V-Sync and changing the settings in my graphics card but still the same thing happens.

Specs:
Windows 8 pre-loaded laptop
Dual Core i3 Processor 2.4ghz
Intel HD Graphics
4gb DDR3

[chirpy13]

I had a similar problem with my old computer.  Usually it would drop to around 40fps  partway into a stage, and then sit there until the stage ended.  Never did figure out the cause or a fix, but I assumed it had something to do with the way the game handles objects, since it happened a lot faster on higher difficulties where there's more bullets and stuff.  Vsync helped a little and made Easy/Normal mode playable, but it didn't really fix anything so much as make it not as bad.  Could maybe try 1/2 frameskip or something too, but it makes things a little harder and it's tough on the eyes.

[Sage Ω (Ultima)]

It might be something related to my HDD. I transfered the game to a 8gb SDHC and it plays perfectly no matter how long I've been playing and the memory stays around 75mb and CPU usage around 8% - 12%.

But still I'd rather use the SDHC for something else and run the game from my HDD.