GPU Bandwidth
Counts the horizontal blanks that 400 full-screen transfers and draws of 320 by 240 pixels take.
| Machine | SCPH-5501 |
|---|---|
| Program | gpu/bandwidth (ps1-tests) |
This is an old revision of this page, as edited by RemmyLee at 05:11, 23 October 2026. Edit this revision | Latest revision
Overview
Each item runs 400 times over a 320 by 240 area: a VRAM read and a VRAM write by DMA channel 2, a VRAM to VRAM copy, a GP0(02h) fill, flat and textured rectangles and quads, each opaque and semi-transparent, and a quad placed a quarter and half off the screen. Root counter 1 counts horizontal blanks across the 400 calls in NTSC mode.1
The program converts the count to milliseconds with 60 frames of 263 lines a second, and to MB/s from 320 x 240 x 2 bytes for each call. Its millisecond figure prints the remainder of that division after the point unscaled, so the horizontal blank count is the measurement to read.1
Results
The counts below are from the run of 25 September 2026. The other five runs differed by 11 or fewer horizontal blanks on every item.2
| Item | Horizontal blanks | MB/s (program) |
|---|---|---|
| VRAM to CPU by DMA | 15,796 | 59 |
| CPU to VRAM by DMA | 12,214 | 77 |
| VRAM to VRAM copy GP0(80h) | 19,202 | 49 |
| Fill GP0(02h) | 1,252 | 759 |
| Rectangle | 7,612 | 124 |
| Rectangle, semi-transparent | 11,473 | 82 |
| Textured rectangle | 15,164 | 62 |
| Textured rectangle, semi-transparent | 15,164 | 62 |
| Quad | 7,747 | 122 |
| Quad, semi-transparent | 11,658 | 81 |
| Textured quad | 39,877 | 23 |
| Textured quad, semi-transparent | 39,879 | 23 |
| Quad, a quarter off the screen | 5,872 | 161 |
| Quad, half off the screen | 4,003 | 237 |
A fill was about six times as fast as a flat rectangle of the same size. A semi-transparent flat rectangle or quad took about 1.5 times the time of an opaque one.2
Semi-transparency added nothing to the textured rectangle or the textured quad. A textured quad took about 2.6 times the time of a textured rectangle of the same size.2
The quad a quarter off the screen took 76% of the time of the full quad, and the quad half off the screen 52%.2
Runs
25 September 2026
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1001.220 ms (hblanks: 15796), speed: 59 MB/s
cpuToVram dT: 774.280 ms (hblanks: 12214), speed: 77 MB/s
vramToVram dT: 1216.13520 ms (hblanks: 19202), speed: 49 MB/s
FillScreen GP0(2) dT: 79.5380 ms (hblanks: 1252), speed: 759 MB/s
Rectangle dT: 482.6040 ms (hblanks: 7612), speed: 124 MB/s
Rectangle (semitransparent) dT: 727.940 ms (hblanks: 11473), speed: 82 MB/s
Rectangle textured dT: 960.15200 ms (hblanks: 15164), speed: 62 MB/s
Rectangle textured (semi) dT: 960.15200 ms (hblanks: 15164), speed: 62 MB/s
Polygon quad dT: 490.14800 ms (hblanks: 7747), speed: 122 MB/s
Polygon quad (semi) dT: 738.12360 ms (hblanks: 11658), speed: 81 MB/s
Polygon quad textured dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad textured (semi) dT: 2527.2940 ms (hblanks: 39879), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.1840 ms (hblanks: 5872), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.10660 ms (hblanks: 4003), speed: 237 MB/s
Done
27 September 2026
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1000.15000 ms (hblanks: 15795), speed: 60 MB/s
cpuToVram dT: 773.14060 ms (hblanks: 12212), speed: 77 MB/s
vramToVram dT: 1216.13520 ms (hblanks: 19202), speed: 49 MB/s
FillScreen GP0(2) dT: 79.1380 ms (hblanks: 1248), speed: 759 MB/s
Rectangle dT: 482.14040 ms (hblanks: 7620), speed: 124 MB/s
Rectangle (semitransparent) dT: 727.940 ms (hblanks: 11473), speed: 82 MB/s
Rectangle textured dT: 960.14200 ms (hblanks: 15163), speed: 62 MB/s
Rectangle textured (semi) dT: 961.420 ms (hblanks: 15165), speed: 62 MB/s
Polygon quad dT: 490.14800 ms (hblanks: 7747), speed: 122 MB/s
Polygon quad (semi) dT: 738.10360 ms (hblanks: 11656), speed: 81 MB/s
Polygon quad textured dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad textured (semi) dT: 2527.1940 ms (hblanks: 39878), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.840 ms (hblanks: 5871), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.10660 ms (hblanks: 4003), speed: 237 MB/s
Done
27 September 2026 run 2
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1000.15000 ms (hblanks: 15795), speed: 60 MB/s
cpuToVram dT: 773.15060 ms (hblanks: 12213), speed: 77 MB/s
vramToVram dT: 1216.13520 ms (hblanks: 19202), speed: 49 MB/s
FillScreen GP0(2) dT: 79.1380 ms (hblanks: 1248), speed: 759 MB/s
Rectangle dT: 482.13040 ms (hblanks: 7619), speed: 124 MB/s
Rectangle (semitransparent) dT: 727.940 ms (hblanks: 11473), speed: 82 MB/s
Rectangle textured dT: 960.14200 ms (hblanks: 15163), speed: 62 MB/s
Rectangle textured (semi) dT: 961.420 ms (hblanks: 15165), speed: 62 MB/s
Polygon quad dT: 490.13800 ms (hblanks: 7746), speed: 122 MB/s
Polygon quad (semi) dT: 738.11360 ms (hblanks: 11657), speed: 81 MB/s
Polygon quad textured dT: 2527.1940 ms (hblanks: 39878), speed: 23 MB/s
Polygon quad textured (semi) dT: 2527.1940 ms (hblanks: 39878), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.840 ms (hblanks: 5871), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.12660 ms (hblanks: 4005), speed: 237 MB/s
Done
27 September 2026 run 3
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1001.220 ms (hblanks: 15796), speed: 59 MB/s
cpuToVram dT: 774.280 ms (hblanks: 12214), speed: 77 MB/s
vramToVram dT: 1216.13520 ms (hblanks: 19202), speed: 49 MB/s
FillScreen GP0(2) dT: 79.1380 ms (hblanks: 1248), speed: 759 MB/s
Rectangle dT: 482.13040 ms (hblanks: 7619), speed: 124 MB/s
Rectangle (semitransparent) dT: 727.940 ms (hblanks: 11473), speed: 82 MB/s
Rectangle textured dT: 960.15200 ms (hblanks: 15164), speed: 62 MB/s
Rectangle textured (semi) dT: 960.14200 ms (hblanks: 15163), speed: 62 MB/s
Polygon quad dT: 490.14800 ms (hblanks: 7747), speed: 122 MB/s
Polygon quad (semi) dT: 738.11360 ms (hblanks: 11657), speed: 81 MB/s
Polygon quad textured dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad textured (semi) dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.840 ms (hblanks: 5871), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.10660 ms (hblanks: 4003), speed: 237 MB/s
Done
27 September 2026 run 4
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1000.11000 ms (hblanks: 15791), speed: 60 MB/s
cpuToVram dT: 773.12060 ms (hblanks: 12210), speed: 77 MB/s
vramToVram dT: 1216.13520 ms (hblanks: 19202), speed: 49 MB/s
FillScreen GP0(2) dT: 79.12380 ms (hblanks: 1259), speed: 759 MB/s
Rectangle dT: 482.13040 ms (hblanks: 7619), speed: 124 MB/s
Rectangle (semitransparent) dT: 726.13720 ms (hblanks: 11470), speed: 82 MB/s
Rectangle textured dT: 960.14200 ms (hblanks: 15163), speed: 62 MB/s
Rectangle textured (semi) dT: 960.13200 ms (hblanks: 15162), speed: 62 MB/s
Polygon quad dT: 491.20 ms (hblanks: 7748), speed: 122 MB/s
Polygon quad (semi) dT: 738.9360 ms (hblanks: 11655), speed: 81 MB/s
Polygon quad textured dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad textured (semi) dT: 2526.14720 ms (hblanks: 39875), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.5840 ms (hblanks: 5876), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.7660 ms (hblanks: 4000), speed: 237 MB/s
Done
28 September 2026
===== 08 GBW GPU BANDWIDTH | BIOS 19951204 System ROM Version 3.0 11/18/96 A
gpu/bandwidth
vramToCpu dT: 1000.12000 ms (hblanks: 15792), speed: 60 MB/s
cpuToVram dT: 773.13060 ms (hblanks: 12211), speed: 77 MB/s
vramToVram dT: 1216.14520 ms (hblanks: 19203), speed: 49 MB/s
FillScreen GP0(2) dT: 79.11380 ms (hblanks: 1258), speed: 759 MB/s
Rectangle dT: 482.14040 ms (hblanks: 7620), speed: 124 MB/s
Rectangle (semitransparent) dT: 726.13720 ms (hblanks: 11470), speed: 82 MB/s
Rectangle textured dT: 960.14200 ms (hblanks: 15163), speed: 62 MB/s
Rectangle textured (semi) dT: 960.12200 ms (hblanks: 15161), speed: 62 MB/s
Polygon quad dT: 491.1020 ms (hblanks: 7749), speed: 122 MB/s
Polygon quad (semi) dT: 738.10360 ms (hblanks: 11656), speed: 81 MB/s
Polygon quad textured dT: 2527.940 ms (hblanks: 39877), speed: 23 MB/s
Polygon quad textured (semi) dT: 2527.1940 ms (hblanks: 39878), speed: 23 MB/s
Polygon quad (1/4 off screen) dT: 372.5840 ms (hblanks: 5876), speed: 161 MB/s
Polygon quad (1/2 off screen) dT: 253.7660 ms (hblanks: 4000), speed: 237 MB/s
Done
References
-
^ a b ps1-tests, gpu/bandwidth. https://github.com/JaCzekanski/ps1-tests.
-
^ a b c d SCPH-5501 output: main/08GBW.txt and the files beside it, with the other runs listed under Runs.
Categories: Hardware tests