Mystic with Spicy O'Clock! 42MHz

[Kay K.M.Mods]

I have two Mystics, which is the Mystic (No.1) that I modified a while ago.
Tested for "Spicy O'Clock!", the original post is here

Spicy O'Clock! is adjustable oscillator used silicone oscillator chip. I think it's the first time it's used on a 68K Mac.
It has a variable range from 35MHz to 51MHz.
For the time being, it is important to create all the data, so I have not tried overclocking above 42MHz...
However, the LC475 is known to work at 42.6MHz. course, serial will not work, so practically it needs to be a clock that is 42MHz or a little slower.
*This may depend on ROM.

Tokyo | Kero's Mac Mods | Vintage Macintosh Mods

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[Drake]

Fast cars, slow computers!
This looks like a fun project, I hope to see more videos!

 

[Kay K.M.Mods]

Fast cars, slow computers!
This looks like a fun project, I hope to see more videos!

Hahaha, this is my takky(No.2). Do you think this is slow

I love the fast things, but 68K is a wasted dream, I love them. I enjoy 68K more than PPC now

 

[Mr. Fahrenheit]

What speed of VRAM are you using in there, and would you be able to run a Norton Utilities 3.1 (System Info) benchmark on it and upload pictures of the different area results (overall, CPU, Graphics, FPU, disk)?

 

[Kay K.M.Mods]

What speed of VRAM are you using in there, and would you be able to run a Norton Utilities 3.1 (System Info) benchmark on it and upload pictures of the different area results (overall, CPU, Graphics, FPU, disk)?

Hi, I used 70Ns Vram for my Mystic. Plz see my blog for the details:

『LC575 overclocking and 70Ns VRAMS』

Oct 24, 2021 correction:In the text, it says that the chip was replaced with a …

ameblo.jp

@JDW said you are familiar with VRAM and you built them.
I'm a little busy, so I'll do benchmarking and validation at another time.
At that time, I will also replace the clock driver chip (MC88916DW80) and experiment, and challenge the limit of overclocking a little more.

 

[Mr. Fahrenheit]

Hi, I used 70Ns Vram for my Mystic. Plz see my blog for the details:

『LC575 overclocking and 70Ns VRAMS』

Oct 24, 2021 correction:In the text, it says that the chip was replaced with a …

ameblo.jp

@JDW said you are familiar with VRAM and you built them.
I'm a little busy, so I'll do benchmarking and validation at another time.
At that time, I will also replace the clock driver chip (MC88916DW80) and experiment, and challenge the limit of overclocking a little more.

Yes, I have built 60ns 512KB VRAM SIMMs for Mac. I used the BetterBit PCB design on GitHub, and I obtained a quantity of Samsung chips (128KB each) 60ns speed. The reason I ask for a benchmark is so I can compare with mine. I don't have overclocked Mystic, but I do have overclocked LC475 @ 33Mhz (I'm not as adventurous as you!).

On my two overclocked LC475 machines, I saw speeds increase with 60ns VRAM vs. 70ns but only in 16 bit color. I noticed a 17% increase in benchmark scores. I tried asking another person who makes VRAM overseas for tests on their hardware, and they had the same speed on their OC 475 with 100ns as I had with my 60ns, and they saw no speed gains. My two 475 that are overclocked have exactly the same benchmark scores. I have tried with 256 and 512KB VRAM, and mixing 60, 70, 80, and 100ns (which doesn't run!).

I don't understand how my two OC 475 could be lower than another person's, and yet how I see a speed gain using 60ns VRAM. If you have knowledge on this subject, I'd love to chat with you to try and figure out whether these 60ns chips have any benefit or not.

 

[Drake]

Yes, I have built 60ns 512KB VRAM SIMMs for Mac. I used the BetterBit PCB design on GitHub, and I obtained a quantity of Samsung chips (128KB each) 60ns speed. The reason I ask for a benchmark is so I can compare with mine. I don't have overclocked Mystic, but I do have overclocked LC475 @ 33Mhz (I'm not as adventurous as you!).

On my two overclocked LC475 machines, I saw speeds increase with 60ns VRAM vs. 70ns but only in 16 bit color. I noticed a 17% increase in benchmark scores. I tried asking another person who makes VRAM overseas for tests on their hardware, and they had the same speed on their OC 475 with 100ns as I had with my 60ns, and they saw no speed gains. My two 475 that are overclocked have exactly the same benchmark scores. I have tried with 256 and 512KB VRAM, and mixing 60, 70, 80, and 100ns (which doesn't run!).

I don't understand how my two OC 475 could be lower than another person's, and yet how I see a speed gain using 60ns VRAM. If you have knowledge on this subject, I'd love to chat with you to try and figure out whether these 60ns chips have any benefit or not.

Let the Benchmark-a-thon begin!

 

[Kay K.M.Mods]

Yes, I have built 60ns 512KB VRAM SIMMs for Mac. I used the BetterBit PCB design on GitHub, and I obtained a quantity of Samsung chips (128KB each) 60ns speed. The reason I ask for a benchmark is so I can compare with mine. I don't have overclocked Mystic, but I do have overclocked LC475 @ 33Mhz (I'm not as adventurous as you!).

On my two overclocked LC475 machines, I saw speeds increase with 60ns VRAM vs. 70ns but only in 16 bit color. I noticed a 17% increase in benchmark scores. I tried asking another person who makes VRAM overseas for tests on their hardware, and they had the same speed on their OC 475 with 100ns as I had with my 60ns, and they saw no speed gains. My two 475 that are overclocked have exactly the same benchmark scores. I have tried with 256 and 512KB VRAM, and mixing 60, 70, 80, and 100ns (which doesn't run!).

I don't understand how my two OC 475 could be lower than another person's, and yet how I see a speed gain using 60ns VRAM. If you have knowledge on this subject, I'd love to chat with you to try and figure out whether these 60ns chips have any benefit or not.

Did u replace a clock driver to MC88916DW80 or 75?
MC88920 has an upper limit about 40MHz.

 

[Mr. Fahrenheit]

Did u replace a clock driver to MC88916DW80 or 75?
MC88920 has an upper limit about 40MHz.

They are stock, except for the 2 resistor swap on the rear of the board to OC to 33Mhz.

 

[nottomhanks]

Hahaha, this is my takky(No.2). Do you think this is slow

I love the fast things, but 68K is a wasted dream, I love them. I enjoy 68K more than PPC now
View attachment 745

What’s with the CF card in the front? How are you doing that?

 

[Kay K.M.Mods]

What’s with the CF card in the front? How are you doing that?

This Takky No.2 had IDE socket cause it's Gazelle 275MHz logic board. Gazelle and Alchemy has IDE and SCSI both connecters.
CF cards r compatible with IDE(ATA) w/out a controller chip. U can buy CF card adapter from anywhere, Amazon, ebay...