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What's faster RAM Doubler or BlueSCSI + Virtual Memory

Forums > Vintage Apple > Software & Operating Systems > Software | System Software (68k)

Sideburn
Tinkerer
California
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Joined: Jun 16, 2023
Posts: 267
Likes: 102
Oct 5, 2023 - #1
Curious what would be faster to increase your physical ram from 8 MB to 16 MB using either 32 but addressing and virtual memory or using Connectix RAM doubler.

I'm sure a BlueSCSI is faster than a physical HD but is it as fast as SSD and how much slower is it than physical RAM?

Connectix RAM doubler uses compression so that'll eat up cpu cycles.

Wondering which method would be fastest.

What do you think?

Androda
TinkerDifferent Board Secretary 2023
USA, Western
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Joined: Sep 25, 2021
Posts: 523
Likes: 581
Oct 5, 2023 - #2
My initial reaction is that RAM Doubler would be faster overall. Compression uses CPU cycles, yes, but those CPU cycles are likely still dramatically faster than reaching all the way out to a hard drive. Even if that hard drive is an SSD.

Sideburn
Tinkerer
California
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Joined: Jun 16, 2023
Posts: 267
Likes: 102
Oct 5, 2023 - #3
Ahh I didn't think about that. I've been experimenting with it. Seems to work ok as a solution until you come out with a PowerBook 100 series ram expansion [face-with-stuck-out-].

Androda
TinkerDifferent Board Secretary 2023
USA, Western
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Joined: Sep 25, 2021
Posts: 523
Likes: 581
Oct 5, 2023 - #4
>> Sideburn said:
until you come out with a PowerBook 100 series ram expansion . Click to expand...
whistles innocently

eric
Administrator
MN
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Joined: Sep 2, 2021
Posts: 1,151
Likes: 1,930
Oct 6, 2023 - #5
IIRC most ram around this era is 70-100ns? BlueSCSI seek is ~1ms. 1ms is 1000000ns right? There's an old analogy (cant remember exactly) that L1 cache is grabbing something off your desk, L2 is going to the mailbox, RAM is like going to the store, disk is like flying to another city :) (something like that anyways)

Also some apps do require physical RAM and wont launch if they detect they're using virtual memory.

Liked by JDWandYoda

JDW
Administrator
Japan
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Joined: Sep 2, 2021
Posts: 2,534
Likes: 1,982
Oct 7, 2023 - #6
>> eric said:
Also some apps do require physical RAM and wont launch if they detect they're using virtual memory. Click to expand...
I concur with Eric. Now that I have a IIci and have cards installed, I am seeing a lot of warnings in the documentation for add-ons about having Virtual Memory switched on. Some things either won't work with Virtual Memory switched on at all, or acceleration will be lost.

Sideburn
Tinkerer
California
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Joined: Jun 16, 2023
Posts: 267
Likes: 102
Oct 10, 2023 - #7
Yeah, I removed it. Too buggy. Lots of illegal instructions using ram hungry apps like Bryce, Premeire etc.

Liked by JDW

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