Eve Spectrum Prototype Tester | Marat Tanalin

Sounds like there’s no bug overlap. I was curious since they fixed a different “30 Hz” bug since it’s not a well-tested mode on many high-Hz monitors. Sounds like it would not be from a related cause.


Another DP cable — still 30 Hz, and still black screen during boot

Purchased another DisplayPort cable, now v1.2 (instead of v1.4) and by another manufacturer (VCOM instead of Hama).

Nothing has changed in terms of DP-specific issues with Eve Spectrum:

  • 30 Hz is the maximum refresh rate available;
  • black screen is displayed during computer boot.

With Dell P2415Q 4K monitor, both issues don’t exist with both DP cables.

So it’s now certain that this is an issue on the Eve Spectrum side, and not a cable issue.

Black screen during boot is probably due to lack of 640×480@75Hz or 640×400/720×400@70Hz

Black screen during boot is probably due to lack of support for 75 Hz at 640×480 in Eve Spectrum:

  • Dell P2415Q does support 640×480@75Hz and does display boot process fine.

  • According to some info in internet, 640×480@75Hz is the mode used by classic (non-UEFI) Award/AMI BIOS during boot.

[Update] Possible boot modes: 640×400@70Hz, 720×400@70Hz

  • There is information that the video modes used for booting VGA-compatible x86 computers are 640×400@70Hz (graphical boot screen) and 720×400@70Hz (text mode).

    This is indirectly confirmed by that Dell P2415Q that displays boot process fine, shows 3840×2160@60Hz as the current mode during boot, so its EDID probably does not have the actual video mode used during boot and some implicit transparent resolution/rate conversion is performed.

    720×400 is also the resolution used by VMware virtual machines during boot.

    So it may make sense to add support for all the three modes (640×480@75Hz, 640×400@70Hz, 720×400@70Hz) to Eve Spectrum to guarantee that the boot process is universally visible on all PCs, or at least for test purposes — to determine what of them is used at least on latest systems with pre-UEFI classic BIOS’es, e.g. my Gigabyte GA-Z68X-UD4-B3 (2011) with Award BIOS.

  • Generally speaking, a universal mechanism of transparent conversion of any input signal (regardless of whether EDID contains the specific mode) to something that can be displayed, would be useful to prevent undesirable situations with no ability to see what the video-source device is outputting.

    And given that via HDMI, boot process was visible on the same system with the same Eve Spectrum monitor, the HDMI controller inside Eve Spectrum apparently already does such video-mode conversion while the DP controller does not.


I’m pretty curious, is that for all modes, or just for 4K?

Many old graphics chips in old graphics cards only can do MST-based (dual-channel) 4K30 to achieve 4K60. There’s pretty much two ways to achieve 4K 60 Hz – and older GPUs end up needing to create a dual-channel over the same cable, to create a pair of 4K30 bandwidth links to do 4K60.

It’s supposed to be transparent to users but older GPU chips capable of DisplayPort 1.2 (even when you use newer DisplayPort cables), sometimes end up needing to use MST (Multi-Stream Transport) protocol to achieve 60 Hz on a 4K display instead of 30 Hz. Newer DisplayPort standards (1.3 and newer) can do 4K 60+ with single stream.

So basically the two totally different different ways for a DisplayPort source to do 4K 60+ Hz. And it’s possible Eve doesn’t support one of the two (MST-based 4K 60 from older GPUs) – maybe something to ask Eve / Lehui. Or perhaps some DisplayPort identification is not being relayed somehow by your particular GPU – I’ve seen DisplayPort 1.3 GPUs advertise themselves as DisplayPort 1.2 protocol devices, and same for monitors. Something to debug, I presume?

This might not be the problem, just maybe an unturned stone to check.


In Windows 10, I noticed ToastyX CRU can also be used to bypass NVIDIA GPU scaling – try testing creating pixel perfect resolutions by creating the custom resolutions in ToastyX than in NVIDIA Control Panel. This is also the recommended solution for Intel GPUs and AMD GPUs too as well;


Just 4K, like if bandwidth was not enough — just like in case of HDMI 1.x where bandwidth is actually not enough. At FHD, I enjoy 144 Hz via DP and 120 Hz via HDMI 1.x.

The same DP cable (each of both cables I tried — v1.4 by Hama and v1.2 by VCOM) provides 4K@60Hz with Dell P2415Q.

Dell P2415Q (2015) is an SST monitor unlike the previous Dell model UP2414Q (2014). This is confirmed in particular, by that GPU scaling works which is known to be impossible on first-generation 4K monitors where MST was used to overcome temporary monitor-hardware limitations.

MST can be used in Dell P2415Q for daisy chaining — connecting another monitor to DP output of P2415Q which (the P2415Q monitor) is then the first and only monitor connected directly to computer as the video source.

That’s interesting, thanks. Though I already found a way to switch resolution without silently switching to GPU scaling: just by selecting the needed resolution not via the main W10’s display settings window, but via the classic “List All Modes” window available via a button in the “Advanced display settings” window.

While we’re at it, does CRU edit the monitor EDID (that I wouldn’t like to take risk of) or does it function somehow else?


No. It is just EDID overrides in the Windows registry. The Windows registry has a mechanism to EDID-override the monitor, and ToastyX edits that. You can do things NVIDIA doesn’t let you do, like edit FreeSync ranges, test extreme overclocked refresh rates (e.g. 500 Hz refresh rates), large vertical totals, etc.

You can use reset-all.exe to undo everything ToastyX has ever done, so there’s an escape hatch included.

P.S. ToastyX is a popular utility in the Blur Busters Discussion Forums


Pixel-perfect (integer) scaling —
testing with a non-computer video source:
SNES Mini game console (1280×720)

SNES Mini (Super Nintendo Classic) is the official retro game console from Nintendo that replicates (with emulation) the most advanced 16-bit console — Super Nintendo.

SNES Mini outputs 1280×720 (HD) via HDMI and has a pixel-perfect mode, but previously edges of pixels inevitably got blurry anyway on all 4K monitors and TVs due to blurry HD→4K scaling by the display itself.

Now with the Eve Spectrum 4K monitor and its “Pixel perfect” upscaling mode, we finally get perfectly sharp image with zero blur when using SNES Mini. And as long as the game does not need aspect-ratio correction and looks fine with square pixels (e.g. “Super Mario World” or “BlackThorne”), the resulting scaled image is also free of horizontal distortion / pixel shimmering. (SNES Mini’s 1280×720 output resolution is too low for pixel-perfect aspect-ratio correction with integer scales used both vertically and horizontally like e.g. bsnes-mt emulator does.)

720×480 instead of 1280×720 via HDMI port #2 [NEW 2021-07-21]

For some reason, SNES Mini output is displayed as 720×480 when the game console is connected to Eve Spectrum via the monitor’s HDMI port #2 instead of #1. So instead of being pixel-perfectly scaled to 4K, the image is blurry and smaller than it should be:

The photos below are taken with SNES Mini connected to Eve Spectrum via HDMI port #1 which is free of this issue.

As with the previous photo set, view full-size photos (not resized by web browser) to see a more detailed image.

SNES Mini user interface

Just in case, the “gear” icon is scaled unevenly by SNES Mini itself when the menu item is current. The monitor’s pixel-perfect scaling is 100% uniform.

Super Mario World

Classic Nintendo game and character.

BlackThorne (BlackHawk)

The SNES version of this game has exactly the same graphics as its DOS version, but lacks original music. This game does not come with SNES Mini by default.

Donkey Kong Country

This game actually needs aspect-ratio correction for proper object proportions, so the image is slightly narrower horizontally than intended, but I still decided to provide a photo of a nostalgic scene in pixel-perfect mode.


I love retro gaming! Makes me want to get some of my old consoles out, but i’ve still got a few NextGen games I would like to complete.


More about pixel-perfect (integer) scaling via HDMI

Additional empirical data collected when connecting via HDMI 1.x again:

  • When booting (loading) computer, the monitor menu displays “1280x1024@60Hz” as the current mode. But in fact, the resulting image looks like it’s first upscaled with blur to an intermediate resolution (probably exactly the 1280x1024 displayed in the monitor menu), then that already blurry image is finally upscaled with no blur with 2×2 square pixels.

    This is probably due to lack of EDID support for 720×400@70Hz, 640×400@70Hz, or 640×480@75Hz modes potentially used by non-UEFI BIOSes (“Award Modular BIOS v6.00PG” in my case) during boot. Black screen via DP during boot has probably the same root, while HDMI controller probably performs some transparent conversion of modes missing in EDID.

  • The interlaced 1080i mode is not scaled and is displayed as “1920x1078” in the monitor menu under Linux only. In Windows 10 and 7, and with the Panasonic GF5 photocamera as the video source, interlaced 1080i is displayed in the monitor menu as “1920x1080” and pixel-perfect scaling does work.

  • At resolutions 1440×900, 720×480, etc., the image is centered instead of scaling, only in the “Pixel perfect” scaling mode of the monitor. In the regular blurry “Maintain aspect ratio” scaling mode, the image is scaled at the same resolutions.

    So a possible reason of centering instead of scaling in the “Pixel perfect” mode is that specific scales (scaling ratios) in the “Pixel perfect” monitor mode are hard-coded into firmware instead of being calculated dynamically and are just wrongly set to 1.0 for corresponding resolutions.

  • The Windows-specific issue that makes it impossible to output 640×480 via HDMI to the monitor directly without prior forced GPU scaling to 800×600, happens in both Windows 10 and Windows 7.

I updated my first report about pixel-perfect (integer) scaling here accordingly, and added “NEW 2021-07-01” mark where reasonable.


Pixel-perfect (integer) scaling —
testing with a non-computer video source:
Panasonic GF5 photocamera (1080i, 480p, 576p)

Tested Eve Spectrum with the Panasonic GF5 (2012, Micro 4/3, MiniHDMI) photocamera as the video source:

  • Works fine with no general issues compared with PC as the video source.

  • The photocamera supports three output modes:

    • 1920×1080i@60Hz (interlaced);
    • 720×480@60Hz (corresponds to the NTSC standard);
    • 720×576@50Hz (corresponds to the PAL standard).

    Just like with PC, pixel-perfect scaling:

    • does work in the 1080i mode (“1920x1080@60Hz” is displayed in the monitor menu);
    • does not work (centered instead) in 720×480@60Hz and 720×576@50Hz modes.

DisplayPort-to-HDMI-2.0 adapter — no luck

Bought a DP-to-HDMI-2.0 adapter — Dell 492-BBXU officially capable of 4K@60Hz. Nothing changed.

  • Same 30 Hz as the maximum refresh rate at 4K.

  • Same black screen during boot.

  • The maximum refresh rate available at FHD is 120 Hz like via HDMI 1.x instead of 144 Hz available via direct DP connection.

The DP end is connected to the computer (which has a DP port capable of 4K@60Hz), the HDMI end is connected to the monitor (which has an HDMI 2.x port capable of 4K@60Hz too).

But at least there is now more clarity about a possible reason of 30 Hz issue

I’m starting to suspect there is something wrong in the way the monitor reports supported graphic modes to the video source.

If Eve Spectrum did not support the part of the DP standard that my graphics card GTX 650 Ti Boost uses for encoding/transmitting data via DP, this would unlikely apply to the DP-to-HDMI scenario given that in this case the monitor thinks it’s HDMI anyway and does not know (or does it somehow?) it’s converted from DP.

So the most probable reason of the 30 Hz limit at 4K is that the monitor reports (regardless of via HDMI or via DP) the list of supported graphic modes in a way that makes my GPU think that the monitor’s maximum refresh rate at 4K is 30 Hz.

E.g. 60 Hz and higher rates for 4K resolution are probably reported in a different way that older GPUs don’t understand regardless of whether via HDMI or via DP. So the issue is probably more fundamental than just a specific-interface-level (HDMI/DP) incompatibility.


you know a man is serious about integer scaling when the words ‘integer’ and ‘scaling’ make up a solid 10% of his introduction post :rofl:

i don’t have anything useful to add, i just wanted to say this is all really cool! :+1:


Yeah, integer scaling is the main/only feature I’m interested in regarding Eve Spectrum, and the thing I investigate and track for years since purchased a 4K monitor in 2015, and the reason why I suggested myself and was then invited as a community tester of Eve Spectrum in the first place. Nice to see another one interested in the feature too. :handshake:


HDMI ports #1 and #2: functionally different?

There is apparently a weird issue with HDMI port #2 of Eve Spectrum:

  • SNES Mini has a fixed output resolution of 1280×720 (HD). But when connected via HDMI port #2, it’s displayed as 720×480 instead — both in terms of image size and the current video mode displayed in the monitor menu/OSD. The issue does not reproduce when using HDMI port #1 — SNES Mini output is displayed properly as 1280×720.

  • In Ubuntu 18.10 (Linux), the maximum resolution available via HDMI port #2 is 960×540 at 60 Hz. In pixel-perfect mode, it was displayed centered without scaling. The issue does not reproduce when using HDMI port #1 — 3840×2160 is the maximum available resolution as expected.

Hopefully a firmware-level issue that could be fixed.

Somewhat good news is that 960×540 is not in the monitor’s EDID, yet it was displayed fine by the monitor. 960x540@60Hz was the current video mode explicitly displayed in the monitor menu/OSD. So it’s apparently technically possible for the monitor to display modes missing in EDID.

Sort of bad news is that 960×540 was displayed without scaling, so looks like specific integer scales for all supported resolutions are hard-coded instead of being calculated dynamically for any input resolution whatever it is.


The snes mini will output 720x480 or 1280x720. Depends on the EDID; you can mess with this using an EDID minder e.g. TMDS-KITU – An Eco Friendly Installation Kit - ConnectPRO

Sounds like there are a few CEA/CVT timing compliance issues.


Thanks. This might be a part of the issue that results in 30 Hz as the maximum refresh rate available with Eve Spectrum at 4K in my case.

As I previously suspected, the monitor probably reports the supported modes in some special not-quite-correct way, so the video-source device thinks the monitor is not capable of higher modes and sends the video signal at a fallback mode. HDMI port #2 probably just reveals this specifics in another, even more special way.

Btw, is there some official info (or at least some more detailed) about 720×480 as a legit SNES Mini output mode along with the usual 1280×720?

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Testing with a non-computer video source:
TV tuner D-Color DC1302HD ✔️

Originally, the third non-computer video source (besides SNES Mini and Panasonic GF5) I planned to test Eve Spectrum with was the hardware player Iconbit HD375W. Unfortunately, the player’s HDMI output apparently failed during the years when the player was unused: it now outputs nothing and the same also takes place with my Dell P2415Q 4K monitor, so this is surely not specific to Eve Spectrum.

As a replacement, I tested the TV tuner D-Color DC1302HD. The device has a built-in (though not quite great in terms of both usability and compatibility with real-world files) video-player and image-viewer functionality and supports multiple output modes:

  • 1920×1080p/i at 60/50 Hz;
  • 1280×720p/i at 60/50 Hz;
  • 720×480p/i at 60 Hz.
  • 720×576p/i at 50 Hz;

Based on testing results, all those modes work with Eve Spectrum correctly and consistently via both HDMI input ports of the monitor. This includes pixel-perfect scaling mode of Eve Spectrum that works correctly too.

The output mode of the TV tuner is explicitly selected manually via its menu. So there is probably no EDID-based video-mode auto­selection magic at all, and that might be the reason why the specifics of the Eve Spectrum’s HDMI port #2 (previously discovered with SNES Mini and Linux) did not reproduce with this video source.

Coincidentally, the TV tuner is based on hardware by the same MStar manufacturer as Eve Spectrum itself.


thanks a lot for keeping up the testing and sharing it with us!

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That would be my guess, yeah. Every display in my house now has an EDID minder attached.

For example I have an old 1080p monitor which (mis)reports its maximum supported resolution as 1080p 30Hz when connected to a MacBook Pro. Added an EDID minder and BAM, a 1080p 60Hz option showed up on the MacBook Pro.

I also use this edid minder to force my iPad to output a 720p signal during streaming video playback to an old 720p only compatible plasma.

I currently force the snes into outputting 480p with this device (you wouldn’t want to use this mode with the EVE because it still renders internally at 720p even though it outputs 480p) TMDS-KITU – An Eco Friendly Installation Kit - ConnectPRO

I also use one of these EDID 101V - Integration Tools | Extron because without it the AMD Radeon drivers incorrectly report virtual super resolution ‘unavailable’ when connected to another of my older TV’s with a d-sub input.

I suspect a 4K EDID minder will solve your issues


If 1080i works then 540p will also work because they have the same timings.

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I would be curious to know whether there are any differences in how the Spectrum handles DTV720x480 and VESA640x480.

852x480 compatibility would also be good to have so I can hook up my Extron DSC 301 HD scaler.