[Demi Lovato's Heroin Spoon]

If you don't mind sacrificing graphics, I'd recommend an autoexec suited to what you're after. You're autoexec.cfg can be found in Steam>steamapps>common>Garry's Mod>garrysmod>cfg. 

If you want to look over console commands yourself, go for it. If not, this is what I use:

r_cheapwaterstart "1"
r_cheapwaterend "1"
r_waterforceexpensive "0"
r_WaterDrawReflection "0"
r_waterforcereflectentities "0"

mat_hdr_level "0"

mat_antialias "0"
mat_filtertextures "1"
mat_forceaniso "0"
mat_trilinear "0"

mat_fastspecular "1"
mat_filterlightmaps "1"
mat_specular "0"
r_dynamic "0"
r_lightaverage "0"
r_maxdlights "0"
r_occlusion "1"

mat_shadowstate "0"
r_shadows "1"
r_flashlightdepthtexture "1"
r_shadowrendertotexture "0"
r_shadowfromworldlights "0"

mat_bumpmap "1"
mat_clipz "1"
mat_colorcorrection "1"
mat_compressedtextures "1"
mat_picmip "2"
r_3dsky "0"

cl_forcepreload "1"
sv_forcepreload "1"
cl_ragdoll_collide "0"
fps_max "300"
mat_reducefillrate "1"
mat_vsync "0"
cl_lagcompensation "1"

con_filter_enable "1"
con_filter_text_out "CMaterial"
cl_showfps "1"

host_writeconfig

If you don't like anything in here, just let me know. If you want to write it yourself, it's a good place to start. You can expect at least a >15 fps increase with it, but I've gained about 30-40, sometimes hitting 200 depending on the map itself.

You can also set your memory usage to high prio, but if your PC is great, talk to your ISP. I've rarely had connection issues on this server unless it crashes. I've played a lot of servers before, some more heavily modified than Dinkleberg's, and there is absolutely no difference at all between connection on both.