Hmm, das deckt sich mit meiner Recherche, es gibt eine kommentierte Datei vom Entwickler
Code:
Interpreting the printout
-------------------------
CACHECHK v3beta2 11/11/95 Copyright (c) 1995 by Ray Van Tassle. (-h for help)
****** WARNING *******
CPU is in V86 mode! Timings may not be accurate!
CMOS reports: conv_mem= 640K, ext_mem= 15,360K, Total RAM= 16,000K
### This is the memory size, as listed in the CMOS (via setup)
"GenuineIntel" 486DX4 100 MHz
### The cpu type & speed. Advanced CPUs will identify themselves. For
### others, the type is derived.
### The speed is determined by instruction timing, and is fairly accurate
### (plus/minus 3 mhz) from 386/16 to P5/120.
Reading from memory.
MegaByte#: --------- Memory Access Block sizes (KB)-----
1 2 4 8 16 32 64 128 256 512 1024 2048 4096 <-- KB
0: 11 11 11 11 11 20 20 20 20 28 -- -- -- æs/KB
### "n:" is the megabyte number. 0 = base memory, 1 = 2nd MB, etc.
### The numbers are how many microseconds it takes to read/write a certain
### number of bytes.
### We can see that 1KB through 16KB takes 11us/KB, 32KB through 256KB takes
### 20us/KB, and 512 KB takes 28us/KB. This is the base memory, so we can't
### go beyond 640KB. So we stop at 512KB.
### The "--" (for blocks of 1MB, 2MB, and 4MB) means that blocks of this size
### were not tested (because they could not be).
### I go up to 4MB, because some lucky folks have 1MB of cache, and if I
### stopped at a 2MB block, there is only one data point of RAM speed.
2: 11 11 11 11 11 20 20 20 20 28 28 28 28 æs/KB
### Megabyte #1 is skipped here. Because I have a memory manager (QEMM)
### loaded. It occupies some of the memory at the beginning of MB#1, therefore
### this MB cannot be allocated, therefore I don't test it.
### However, I can check a blocksize of 4MB. This means that it reads from
### address 0x0200000 through 0x05fffff.
### We now have 4 data-points of actual RAM speed.
### By inspection, we see that there are two breakpoints in the memory
### access speed. The first at 16kb, the second at 256kb. This is as it
### should be, as this is an Intel 486/100 (with 16kb of L1 cache), and 256kb
### of L2 cache on the motherboard. An AMD 486/100 has 8KB of L1 cache.
### A Pentium has 8kb data cache and 8kb of instruction cache.
### CACHECHK only tests data, so P5's will show 8kb of L1 cache.
3 4 5 6 7 8 9 <--- same as above.
### The speeds of megabyte 2 thru megabyte 9 are all the same.
### Actually, this is a small fib. Since mb#9 is the last full mb being
### tested, we clearly can't be using block sizes of 2MB or 4MB. And for
### mb#8, we can't use block size of 4MB. Those entries actually have
### "--". But the numbers which *are* there are the same.
This machine seems to have both L1 and L2 cache. [read]
### This is reading. Writing will say ["write]".
L1 cache is 16KB -- 103.3 MB/s 10.2 ns/byte (262%) (186%) 3.9 clks
L2 cache is 256KB -- 55.3 MB/s 19.0 ns/byte (140%) (100%) 7.2 clks
Main memory speed -- 39.3 MB/s 26.7 ns/byte (100%) [read] 10.2 clks
L1 cache is 16KB -- 102.8 MB/s 10.2 ns/byte (261%) (185%)
L2 cache is 256KB -- 55.3 MB/s 19.0 ns/byte (140%) (100%)
Main memory speed -- 39.3 MB/s 26.7 ns/byte (100%) [read]
### The L1 cache is 262% (two and a half times) faster than RAM.
### The L2 cache is 140% (one and a half times) faster than RAM.
### The L1 cache is 186% faster (almost twice as fast) as the L2 cache.
### It takes an average of 3.9 clock cycles to read a 32-bit longword from
### the L1 cache into a 32-bit register, 7.2 cycles from L2, and 10.2 from RAM.
Effective read RAM access time is 106ns (a RAM bank is 4 bytes wide).
### This is the *measured* access speed of the RAM. On a 486, this
### is 4 times the "main memory speed" (above example is 4 * 26.7), because
### a 486 has a 32-bit (4 byte) path between RAM and the CPU. For a P5,
### this will be 8 times, because the P5 has a 64-bit (8 byte) path.
### Note that this is NOT the speed of your RAM chips---it is the measure of
### how fast your RAM is being driven.
###
### This is VERY dependent on the "DRAM Burst Cycle" settings in your BIOS
### setup. This computer has an AMI bios, where I can set it to certain
### values. The fastest it will allow is 3-2-2-2. The slowest
### it will allow is 5-4-4-4. With this slow setting, I get:
### Main memory speed -- 24.9 MB/s 42.1 ns/byte (100%) [read]
### Effective read RAM access time is 168ns (a RAM bank is 4 bytes wide).
### This is much slower, BUT it might let me use slower (i.e., cheaper) RAM
### chips.
### Note that *many* motherboards will NOT let you fiddle with these settings.
### The 486 (and Pentium) always fill the entire cache line (16 bytes), so
### it is NOT possible to get just one byte from the memory; it always
### grabs all 16 bytes in that block.
je kürzer die ns desto besser, je kleiner die clks, desto besser. Aber die Arbeitsspeichersache habe ich auch noch nicht verstanden.