First off my PC specs are:
Graphics Card - Gigabyte Radeon 7870 OC
Processor - AMD FX8120 @ 3.89Ghz 8 core processor
Motherboard - Sabertooth 990FX R2.0
Case - Zalman Z11 Plus
RAM - Corsair Vengance 8GB 1866Mhz
HDD - Seagate Momentus XT 750gb Hybrid Hard Drive
Power Supply - Corsair TX750 (Crossfire in the future)
When I play Gmod on normal maps I get like 150-300 fps, but when I go on some custom maps my FPS drops to 25-30, this should not happen!!! This is unplayable and i don't understand why it happens, if anyone can help me it would be helpful
It's to do with the way Gmod handles RAM allocation - very badly.
Custom maps require Gmod to allocate a lot of RAM, and constantly read/write the data.
It is notoriously bad for this, and everyone will experience this problem, no matter how good your PC is.
I think there is a way to workaround this problem, but I don't know what it is. Google it, there will be a guide somewhere