All Questions
Tagged with memory performance
14
questions
10
votes
5
answers
6k
views
When did the PC bus start slowing access to video RAM?
The PC architecture, from the original IBM PC onward, has always been designed around the idea that video memory will be on an expansion card. This was an unusual design decision; most 80s computers ...
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18
votes
1
answer
2k
views
What did it cost the 8086 to support unaligned access?
The Intel 8086 supported unaligned loads and stores of 16-bit data, e.g. mov ax, foo was guaranteed to work even if foo was odd.
What did this cost, in terms of performance and chip area, compared to ...
- 63.1k
9
votes
1
answer
3k
views
Why was the Nintendo 64 bad at textures?
The Nintendo 64 had a reputation for being great at drawing triangles, but not so good at texturing them, so that many games fell back on heavy use of untextured (though Gouraud shaded) triangles, ...
- 63.1k
5
votes
2
answers
1k
views
How fast was Rambus compared to regular EDO RAM?
The Nintendo 64 used Rambus RDRAM. This was an unusual choice, e.g. the PlayStation used regular EDO RAM which I gather most consoles and computers did at the time.
As I understand it, Nintendo chose ...
- 63.1k
4
votes
1
answer
296
views
How long would a 41256 take to do 4 accesses in fast page mode?
I have been surprised at how little use eighties computers made of fast page mode access to RAM. (A notable exception being the Sinclair Spectrum, which used it to get the necessary bandwidth to video ...
- 63.1k
8
votes
4
answers
865
views
Does fast page mode apply to ROM?
Starting with the 4116, RAM chips from the late seventies supported fast page mode, where if you were reading nearby – particularly, successive – words, you didn't need to supply both row and column ...
- 63.1k
7
votes
4
answers
4k
views
Amiga memory bandwidth
Looking at a timing diagram for the various kinds of memory access occurring on the Amiga http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node02D4.html it seems to be saying that video ...
- 63.1k
6
votes
2
answers
285
views
Can fast page mode depend on the first data retrieved?
As early as the seventies, some computers used RAM in page mode, in which you can read two or more words from sequential locations in rapid succession by only supplying the column address once, and ...
- 63.1k
13
votes
3
answers
2k
views
When did CPUs start using page mode DRAM?
According to https://en.wikipedia.org/wiki/Dynamic_random-access_memory#Page_mode_DRAM
Page mode DRAM is a minor modification to the first-generation DRAM IC interface which improved the ...
- 63.1k
17
votes
9
answers
4k
views
Z80 and video chip contending for random access
Back in the 8-bit days, I used 6502 computers, where the story about memory access was easy to understand. RAM chips of the late seventies and early eighties could do 2 MHz (or a bit more e.g. 2.6 in ...
- 63.1k
18
votes
5
answers
4k
views
80s DRAM chips: one per bit of data bus width?
As I understand it, in the eighties the typical way of handling memory was one RAM chip per bit of data bus width. Suppose you were building a 16-bit machine and you wanted to give it 32K of RAM, you ...
- 63.1k
16
votes
3
answers
3k
views
Speed of early ROM versus RAM chips
In the late seventies, up through around 1981, the maximum access speed of off-the-shelf RAM chips was around 2.6 MHz.
Did the same speed limit apply to ROM chips of the same era? If not, what would ...
- 63.1k
21
votes
2
answers
3k
views
68000 and memory access speed
On the one hand, I get the impression that memory chips around 1980 could be accessed no faster than 2 MHz.
On the other hand, the 68000, introduced in 1979, had a typical clock speed of 8 MHz.
How ...
- 63.1k
12
votes
6
answers
2k
views
Memory-limited workloads
I'm trying to figure out whether computing workloads, particularly those related to science and engineering, have historically been limited by memory or CPU. (By the former, I mean not memory access ...
- 63.1k