VOGONS


486DX2-66 Write-Back and Turbo mode

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Reply 20 of 29, by Disruptor

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Dido wrote on 2023-02-09, 15:51:
Disruptor wrote on 2023-02-08, 17:10:
aitotat wrote on 2023-02-08, 16:04:

Why the speedsys result is like that? I don't know, maybe the CPU doesn't properly halt when instructed?

Perhaps it uses CLI / STI to interrupt interrupt requests.

What does this mean? CPU problem or chipset incompatibility?

No, just a kind of increasing the quality of a benchmark.
A benchmark should not be influenced by interrupts or background activity.

Reply 21 of 29, by CoffeeOne

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Dido wrote on 2023-02-09, 15:48:

I can test and post results with the settings you suggested, but I don't know how to set the cache in 2-1-1-1 mode.
In BIOS "Cache Burst Read" and "Cache Write Cycle" are with value "2T" and can't be changed.
....

You must disable AUTO configuration, then you can change values.
Cache Write Cycle 2 is already max speed. But Cache Burst Read you can set to 1.
Also DRAM Fastest instead of Faster.
Some other parameters, too.

Can re-run speedsys after you have done it?

Reply 22 of 29, by Dido

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CoffeeOne wrote on 2023-02-09, 19:22:
You must disable AUTO configuration, then you can change values. Cache Write Cycle 2 is already max speed. But Cache Burst Read […]
Show full quote

You must disable AUTO configuration, then you can change values.
Cache Write Cycle 2 is already max speed. But Cache Burst Read you can set to 1.
Also DRAM Fastest instead of Faster.
Some other parameters, too.

Can re-run speedsys after you have done it?

Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by more than 12%.

Here are the exact results and screenshots with BIOS settings and Speedsys benchmark:

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s ( +1.6%)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6%)
Memory throughput - 24.61 MB/s (+12.1%)

Reply 23 of 29, by CoffeeOne

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Dido wrote on 2023-02-11, 13:00:
Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by mor […]
Show full quote
CoffeeOne wrote on 2023-02-09, 19:22:
You must disable AUTO configuration, then you can change values. Cache Write Cycle 2 is already max speed. But Cache Burst Read […]
Show full quote

You must disable AUTO configuration, then you can change values.
Cache Write Cycle 2 is already max speed. But Cache Burst Read you can set to 1.
Also DRAM Fastest instead of Faster.
Some other parameters, too.

Can re-run speedsys after you have done it?

Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by more than 12%.

Here are the exact results and screenshots with BIOS settings and Speedsys benchmark:

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s ( +1.6%)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6%)
Memory throughput - 24.61 MB/s (+12.1%)

Hello,

You forgot DRAM Write WS set to => 0. 😁
Maybe you can set also Latch Local Bus to T2. And Transparent instead of Synchronize, that would improve Video speed, you will see it in Speedsys, too.

Reply 24 of 29, by Dido

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CoffeeOne wrote on 2023-02-11, 13:16:
Hello, […]
Show full quote
Dido wrote on 2023-02-11, 13:00:
Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by mor […]
Show full quote
CoffeeOne wrote on 2023-02-09, 19:22:
You must disable AUTO configuration, then you can change values. Cache Write Cycle 2 is already max speed. But Cache Burst Read […]
Show full quote

You must disable AUTO configuration, then you can change values.
Cache Write Cycle 2 is already max speed. But Cache Burst Read you can set to 1.
Also DRAM Fastest instead of Faster.
Some other parameters, too.

Can re-run speedsys after you have done it?

Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by more than 12%.

Here are the exact results and screenshots with BIOS settings and Speedsys benchmark:

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s ( +1.6%)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6%)
Memory throughput - 24.61 MB/s (+12.1%)

Hello,

You forgot DRAM Write WS set to => 0. 😁
Maybe you can set also Latch Local Bus to T2. And Transparent instead of Synchronize, that would improve Video speed, you will see it in Speedsys, too.

Hi, next week I will test with these additional settings and upload the results 😀

Reply 25 of 29, by Dido

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CoffeeOne wrote on 2023-02-11, 13:16:
Hello, […]
Show full quote
Dido wrote on 2023-02-11, 13:00:
Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by mor […]
Show full quote
CoffeeOne wrote on 2023-02-09, 19:22:
You must disable AUTO configuration, then you can change values. Cache Write Cycle 2 is already max speed. But Cache Burst Read […]
Show full quote

You must disable AUTO configuration, then you can change values.
Cache Write Cycle 2 is already max speed. But Cache Burst Read you can set to 1.
Also DRAM Fastest instead of Faster.
Some other parameters, too.

Can re-run speedsys after you have done it?

Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by more than 12%.

Here are the exact results and screenshots with BIOS settings and Speedsys benchmark:

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s ( +1.6%)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6%)
Memory throughput - 24.61 MB/s (+12.1%)

Hello,

You forgot DRAM Write WS set to => 0. 😁
Maybe you can set also Latch Local Bus to T2. And Transparent instead of Synchronize, that would improve Video speed, you will see it in Speedsys, too.

Screenshots with BIOS settings and Speedsys benchmark with added 2 extra settings suggested by CoffeeOne - DRAM Write WS -> 0 and Latch Local Bus -> T2:
As evidenced by the tests with the settings suggested by CoffeeOne the performance has improved significantly. Thanks!

TEST 3 (Settings suggested by CoffeeOne (TEST 2) + new suggested (DRAM Write WS -> 0 and Latch Local Bus -> T2))
Data cache L1 ( 8 KB)- 69.91 MB/s (+13% from TEST 1 and +11% from TEST 2 )
Data cache L2 (256 KB)- 49.41 MB/s (+42% from TEST 1 and +17% from TEST 2 )
Memory throughput - 31.32 MB/s (+43% from TEST 1 and +27% from TEST 2 )

Previous test results (from this thread):

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s (+1.6% from TEST 1)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6% from TEST 1)
Memory throughput - 24.61 MB/s (+12.1% from TEST 1)

Reply 26 of 29, by CoffeeOne

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Dido wrote on 2023-04-05, 16:29:
Screenshots with BIOS settings and Speedsys benchmark with added 2 extra settings suggested by CoffeeOne - DRAM Write WS -> 0 an […]
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CoffeeOne wrote on 2023-02-11, 13:16:
Hello, […]
Show full quote
Dido wrote on 2023-02-11, 13:00:
Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by mor […]
Show full quote

Hi, I changed the settings as you suggested and the L2 cache performance increased by more than 20% and memory throughput by more than 12%.

Here are the exact results and screenshots with BIOS settings and Speedsys benchmark:

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s ( +1.6%)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6%)
Memory throughput - 24.61 MB/s (+12.1%)

Hello,

You forgot DRAM Write WS set to => 0. 😁
Maybe you can set also Latch Local Bus to T2. And Transparent instead of Synchronize, that would improve Video speed, you will see it in Speedsys, too.

Screenshots with BIOS settings and Speedsys benchmark with added 2 extra settings suggested by CoffeeOne - DRAM Write WS -> 0 and Latch Local Bus -> T2:
As evidenced by the tests with the settings suggested by CoffeeOne the performance has improved significantly. Thanks!

TEST 3 (Settings suggested by CoffeeOne (TEST 2) + new suggested (DRAM Write WS -> 0 and Latch Local Bus -> T2))
Data cache L1 ( 8 KB)- 69.91 MB/s (+13% from TEST 1 and +11% from TEST 2 )
Data cache L2 (256 KB)- 49.41 MB/s (+42% from TEST 1 and +17% from TEST 2 )
Memory throughput - 31.32 MB/s (+43% from TEST 1 and +27% from TEST 2 )

Previous test results (from this thread):

TEST 1 (Default settings)
Data cache L1 ( 8 KB)- 61.97 MB/s
Data cache L2 (256 KB)- 34.89 MB/s
Memory throughput - 21.95 MB/s

TEST 2 (Settings suggested by CoffeeOne)
Data cache L1 ( 8 KB)- 62.95 MB/s (+1.6% from TEST 1)
Data cache L2 (256 KB)- 42.41 MB/s (+21.6% from TEST 1)
Memory throughput - 24.61 MB/s (+12.1% from TEST 1)

Nice.
But you are still not finished.
Now you need a new BIOS. You want to use the famous BIOS with the "L2 WB fix". That will increase memory throughput even more.
Re: Evolution of a Socket3 System to a POD @100MHz

Reply 27 of 29, by BitWrangler

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Have the same board around, just getting interested in write back support and the weirdnesses thereof, intending to try using it on Cyrix DX2 and cousins.

One thing I was gonna say is that a lot of the later writeback intels seemed to be enhanced version with 16kb, this doesn't look like one though with that drop at 8kb.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 28 of 29, by CoffeeOne

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BitWrangler wrote on 2023-04-06, 04:08:

.......
One thing I was gonna say is that a lot of the later writeback intels seemed to be enhanced version with 16kb, this doesn't look like one though with that drop at 8kb.

I don't think that is correct. Only Intel DX4 &EW have 16kb L1 and L1 write back. No (or very little) DX2 ones.
It is true for AMD, AMD sold 5x86 CPUs as DX2. Those have 16kb L1 and L1 WB.

Reply 29 of 29, by BitWrangler

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Yah, been seeing a lot of 486 specs over the last couple of weeks as I am trying to nail down Cyrix WB behavior and details, and register settings, and see things in searches about other 486 and think "oh that's interesting" but don't do the deep dig, because I'm tryna track cyrix info at the time, but anyway, it was maybe something about the CPUID 470h version, which was not widespread. Think the info was an IBM table, it might have been a CPU that didn't get an S-Spec because it was IBM production. (Of Intel CPU, not Cyrix, the confusing buggers)

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.