Eve Spectrum Prototype Tester | Marat Tanalin

4K@60Hz via DP is not above the nVidia spec unless you consider DP itself above the nVidia spec.

4k@30Hz is an HDMI-1.x-specific limitation just due to its limited bandwidth:

3840x2160 at 30Hz or 4096x2160 at 24Hz supported over HDMI.

Bandwidth of DisplayPort 1.2 is enough even for 4K@75Hz.


Quick update: Looks like the issue with inability to use 640×480 in Windows is HDMI-specific and does not reproduce with DisplayPort. Added a note into the corresponding previous comment.

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Yes I do as it’s not listed as a regular output for that model. Therefore not officially supported by the hardware. That being said, as long as the card manufacturer implemented DP correctly, I agree it should work. Did you try my suggestion from my previous comment? Perhaps a custom resolution/refresh profile in the nvidia control panel will force it to work.

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Pressing the “Test” button in the nVidia CP window for creating a custom resolution 3840×2160@60Hz results in the same jerky 30 Hz, both perceptually and according to the refresh rate shown in the monitor menu.

Again, 4K@60Hz works on Dell P2415Q 4K monitor like a charm under the same conditions.

And just noticed: you referred to a different GPU without the “Boost” part in the model name.
GTX 650 Ti Boost does officially support DisplayPort:


3840x2160 at 30Hz or 4096x2160 at 24Hz supported over HDMI. 4096x2160 (including 3840x2160) at 60Hz supported over Displayport.

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Ah, that’s my bad then. I didn’t even notice. And I’m out of ideas of what the issue may be. Hopefully Eve can help find a solution.


Pixel-perfect (integer) scaling — photos in games at 640×480

Below are photos of Eve Spectrum screen when displaying games running at 640×480 at two “Picture” → “Aspect Ratio” monitor settings, shown side by side:

  • “Pixel perfect” (the exclusive Eve Spectrum mode with no blur);
  • “Maintain aspect ratio” (regular blurry scaling).

View full-size photos (not resized by web browser) to see individual pixels. :slight_smile:

Moto Racer (Steam version)

POD Gold (GOG version)

Command & Conquer: Red Alert II (Origin version)


Red Alert II best C&C ever. Played the shit out of that game back in the day

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When I was strobe tuning, I noticed some 24/30Hz issues on DisplayPort that I bugreported and Eve’s Lehui fixed them. I wonder if the fix needs to be repeated on HDMI?

In older firmwares, V100R840(ish) or earlier, switching from above 60 Hz temporarily to 24 Hz then back above 60 Hz, caused a lot of frame skipping to appear at 60 Hz until the monitor was unplugged/power cycled. Also 4K144 frameskipping was fully fixed during the course of my debugging the strobe tuning.

All these issues reported by me were fixed on MP firmwares AFAIK (V100R852 and newer), at least on DisplayPort.

Hearing the DP-vs-HDMI behavior difference, I imagine a retest by one of y’all on HDMI is in order, just in case, for the next firmware download.

For my test I did during strobe tune, I recommend Hz-switch tests 60-24-60, and 144-30-144, as well as 50-30-50. Anything non-divisible below 50Hz seemed to trigger my old issue. Anything below 50Hz turns on a repeat-refresher engine (like internal 120Hz to repeat-refresh 24Hz five times) in firmware, and that logic needed to be turned off when switching to 50Hz or up. Almost all brands of gaming LCDs do 24Hz and 30Hz via internal repeat-refresh logic (kind of a fixed Hz equivalent of VRR LFC), Eve included. Few people run high-Hz LCDs at such low Hz, but might be a cause of triggering frame skipping issues at higher Hz, via a specific obscure missed mode-change-reinitialization that ended up being required.

Easy bugfix (copy DP fix to HDMi logic) if this is determined to be from the same cause.


Hello, Mark. While what you said makes sense in general, I’m not sure how this is related to the issues I described here in this thread.

My only issue with HDMI was forced undisableable 640×480→800×600 prescaling via GPU under Windows before outputting to the monitor. And this issue is also a functional difference between HDMI and DP regarding Eve Spectrum, because with DP, 640×480 is outputted directly to the monitor, without prescaling it to 800×600.

30 Hz as the maximum available refresh rate via HDMI 1.x is not an issue in my case, but a natural and expected result of using HDMI 1.x with its limited bandwidth only capable of 4K@30Hz.

The real issues in my case are mainly with DisplayPort:

  • 30 Hz via DisplayPort 1.2 using a DP 1.4 cable (officially backward compatible with DP 1.0-1.3), while the same cable provides 4K@60Hz with my Dell P2415Q monitor under the same conditions.

  • Black screen during computer boot until Windows 10 is loaded, so there is no way to change BIOS settings or choose a different OS or a different drive to load an OS from.

  • Black screen in Windows 7 and therefore inability to use Windows 7 with Eve Spectrum at all.


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: