From 265dfa75417e80686d0cb12a27d7a8a25c299b25 Mon Sep 17 00:00:00 2001 From: Stefan Koelle Date: Sun, 13 Sep 2026 11:40:59 +0200 Subject: [PATCH] Add GemBench 6.31 results to ET4000 page --- retro/et4000-experiment/index.njk | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/retro/et4000-experiment/index.njk b/retro/et4000-experiment/index.njk index 39af049..ff778d4 100644 --- a/retro/et4000-experiment/index.njk +++ b/retro/et4000-experiment/index.njk @@ -37,6 +37,25 @@ parent: "/retro/"

How It Got Working

Solving it came down to giving the supply the headroom it needed. With a properly beefed-up power supply to cover the 5V and 12V rails, plus a cooling solution for the card, the stability problems went away. The ET4000 now drives higher resolutions and more colors than the Shifter chip can natively produce, turning the "High" machine into a genuine workstation.

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GemBench Results

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How does the ET4000 actually perform on an 8 MHz 68000? GemBench 6.31 gives the answer. The reference system is an STE 68000 with stock Shifter, the "High" machine has the ET4000 running at 1024x768x256.

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TestRatioWhat it means
VDI Text269%Nearly 3x faster, the ET4000 handles text rendering
VDI Small Text174%Noticeably faster
VDI Graphics188%Drawing and line work is quicker
VDI Enquire160%Screen queries are faster
VDI Text Effects112%Slightly faster
GEM Dialog Box97%Barely affected
Integer Division99%CPU-bound, unchanged
RAM / ROM Access99%CPU-bound, unchanged
Justified Text63%Slower, GEM still handles this via CPU
GEM Window69%Slower, GEM window management adds overhead
VDI Scroll53%Slower, scrolling is CPU-bound despite the card
Blitting32%Much slower, no hardware BitBLT on the ET4000
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The overall average sits at 100%, which is misleading. The picture is split: anything the ET4000 can accelerate (text, graphics drawing) runs significantly faster, while GEM-level operations that still go through the CPU (window management, scrolling, blitting) are dragged down by the overhead of driving a higher resolution through the ISA bus. In day-to-day use, the VDI gains are what you see and feel: text is crisp, menus pop up quickly, and drawing applications are noticeably more responsive.

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The Context

FPGA cores on MiSTer and MiST still only emulate the native ST Shifter, with no ET4000 emulation on the horizon given the FPGA resources it would require. So the real hardware approach remains the only way to get those higher resolutions, and now it works in the Mega ST 4 "High" machine with its dedicated monitor.