Framebuffer

[bowserjps]

There is a laptop (my aunt's), and a desktop (mine). In Mario Kart 64, they both go the same speed (found out by disabling frame limit) (400FPS). But, when I enable "Copy Framebuffer to RDRAM, the laptop goes about 80FPS, but the desktop goes at an unexceptional 40FPS. The Laptop has a Pentium M 1.73, an Intel Graphics Media Accelerator 900, and about 512 MB of RAM. The Desktop specifications are shown below (I hope). Does the laptop have a special Architecture that is better than the Desktop? Here is the DxDiag of the desktop and the laptop specs if you need more information to tell.

 

[Smiff]

copy speed does depend on graphics card make and motherboard features, although i haven't done much testing to find out how they vary.. i know nvidia used to be slower than most.

edit: ah your desktop has a TurboCache 6200. thats probably using the bus already and impacting framebuffer copies. just a guess.

 

[axcc123]

Copy Framebuffer to RDRAM slows down emulation

 

[Allnatural]

Does the laptop have a special Architecture that is better than the Desktop?

Yes and no. Framebuffer effects require sending data back and forth over the AGP bus, something the bus isn't particularly good (fast) with. Theoretically, the integrated chip in your laptop should be much faster because it shares system memory. Of course, integrated chips typically have a whole host of other problems, so they're generally not recommended for gaming, including emulation.

Feel free to correct me if I'm wrong...

 

[squall_leonhart]

its strange becoz data can be passed faster along the agp bus then to system ram...

 

[Doomulation]

Of course not. Data is transfered to and from RAM all the time so it needs to be fast.

 

[Smiff]

shared memory systems might be faster than AGP or PCIe cards at framebuffer copies because the main memory bus, which generally has a lot more bandwidth, is used for both operations - but its still not "fast" (hence the huge slowdown still) because the memory is not unified in any way, and because its shared of course. i have an nForce 430 system i might try this on later.
btw does that intel 915 render ok generally? we need more info on the capabilites of modern laptop integrated chipsets, for the support pages.

 

[squall_leonhart]

i can tell you now the 915 does not render well.. it has limited dx 9 support (including pixel shader 2.0) but its far from being an efficient render device... my ex has on.. very slo playing sims and age of empies 3..

a friend of mine also has a 915 based system,. and i loaded some roms on his computer with PJ64 (dx8 plugin) and it doesn't play very quickly.

 

[SeymourOmnis]

well, at least in is laptop he can play Mario Kart at a steady 80FPS, higher than normal, it means that he can play MK64 at full speed even when enabling the framebuffer.

 

[Poobah]

Glie64 with Gonetz' modification of Hacktarux' wrapper can achieve the same thing in Mupen64.

 

[squall_leonhart]

it could also depend on the cpu used as well.

 

[bowserjps]

SeymourOmniswell, at least in is laptop he can play Mario Kart at a steady 80FPS, higher than normal, it means that he can play MK64 at full speed even when enabling the framebuffer.

Actually, I found out that Intel GPUs can emulate framebuffer very well.

 

[Doomulation]

Actually, I found out that Intel GPUs can emulate framebuffer very well.

The bottleneck is not the GPU, but the actual transport to and from the GPU, the AGP or PCI Express.

 

[bowserjps]

So, is AGP better than PCI Express, because my GPU uses PCI Express x16 and doesn't emulate framebuffer at ~80fps.

 

[Doomulation]

No, PCI Express is better than AGP, but they're both slow in terms of framebuffer.

 

[bowserjps]

Oh, so a gpu that shares system memory speed up framebuffer copies

 

[Doomulation]

Yes, since it does not need to be transferred to and from the GPU.

 

[bowserjps]

I tried the plugin TR64 OpenGL 0.8.8, selected uCode 1 (Mario Kart 64), and said Enable Framebuffer, and actually, I got an exceptional ~140fps.

 

[Doomulation]

There may also be additional technical details in this whole mess. And Glide64 w/ Hacktarux's wrapper shows that framebuffer can be done, even on dedicated cards. As it stands, however, Jabo's plugin's framebuffer (copy from RDRAM) is slow, at least for now.

 

[Jabo]

Most integrated graphics made in late 2004-present are more capable for running 1.6, in fact I'm running on an integrated ATI 200M run now.

As far as the frame buffer emulation goes, the option you all are referring to is a diagnostic its not intended to run with. If you have a game that lacks proper frame buffer emulation like mario kart my suggestion would be join the beta program and work with us on getting it emulated properly.

I hope people do notice that PJ's frame buffer emulation is visually high in quality.