The direct answer
For a fixed Windows streaming PC, start with the display and source you must preserve, then buy the PCIe card whose current manufacturer matrix matches it. Elgato’s 4K Pro documents PCIe 2.0 x4, HDMI 2.1 input and output, HDR/VRR passthrough, and capture up to 2160p60. That makes it a clear fit when the playing display needs a high-refresh HDMI 2.1 route while OBS receives a separate capture feed. AVerMedia’s GC575 is also a PCIe 4K-class card, but its own current quick guide and manual should be checked against the exact console and monitor mode before purchase.
This is a desk-researched comparison of published specifications and support documents, not a latency benchmark or a claim that either card works with every console, monitor, cable, GPU, or application. Capture and passthrough are separate promises. A card can preserve a high-refresh signal to the player display while delivering a lower capture mode to software. Treat that difference as the main purchase question rather than reading a single headline resolution as a guarantee.
Sources and references
Map the route before comparing features
Write the route on paper: console or gaming PC, HDMI cable, card input, card output, player display, capture software, encoder, and destination. Then record the mode at every point: resolution, refresh rate, HDR or SDR, VRR state, audio format, and whether the source uses HDCP. A 4K120 display path is not proof that OBS will receive 4K120, and an excellent capture mode does not help if the player display loses VRR or game mode. The source, card, cable, display, and host all have to agree.
The host is part of the route. Elgato states that 4K Pro is a Windows-only internal PCIe product and gives separate requirements for its own software; it also notes that requirements in OBS or other applications can differ. Confirm a physical x4-or-better slot, lane availability, GPU clearance, cooling, and the motherboard manual before ordering. An internal card is tidy in a permanent desktop, but it is not a good answer for a laptop, a small system with no viable slot, or a machine where adding a card disables an important storage or expansion path.
Sources and references
Why the Elgato route is easy to explain
Elgato publishes unusually useful distinctions for this decision. Its technical page lists HDMI 2.1 passthrough up to specific high-resolution and high-refresh modes while listing capture up to 2160p60, and its matrix says software can affect which listed capture modes are usable. It also explicitly excludes Display Stream Compression and says the PlayStation 5 Pro’s 8K output format is not supported for passthrough or capture. Those limits are not a weakness in the documentation; they are the kind of limitation a buyer needs before rebuilding a gaming desk around a card.
Choose 4K Pro when the confirmed requirement is a Windows PCIe build, an HDMI 2.1 player-display path, and a documented OBS-compatible capture route up to the required capture format. Do not choose it merely because an 8K label appears in the passthrough specification. A live stream is normally limited by the capture mode, encoder, upload, platform ingest, and viewer playback path long before a display-passthrough maximum becomes a visible audience benefit.
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What to verify on the AVerMedia card
AVerMedia’s Live Gamer 4K 2.1 is not interchangeable with every card that carries a similar 4K or HDMI 2.1 label. Use its current product page, quick guide, and user manual to check the supported input, capture, passthrough, system, and audio conditions for the intended build. In particular, distinguish the signal that reaches the display from the signal the card exports to the capture application. A player may reasonably care about a high refresh monitor path while the stream only needs a stable 1080p60 or 1440p60 production feed.
The sensible reason to select the GC575 is a verified match to that complete route, not a generic belief that one manufacturer is better. Build a small compatibility table before buying: source model and firmware, desired display mode, capture mode, HDR plan, VRR plan, audio output setting, host slot, operating system, capture application, and destination output. If any row is unknown, do not convert the unknown into a purchase assumption. Ask the manufacturer or retailer about the exact unresolved case and retain a return path.
Sources and references
The two failures that surprise first-time builders
Protected content is one. Capture cards are built for unencrypted HDMI, and platform apps, console settings, and HDCP behavior can prevent an expected source from appearing. Do not troubleshoot a black preview by randomly changing every OBS property. First confirm the source is unprotected and the card sees its input, then test a known-good cable and display route, then test the capture application. Keep the player display attached while testing because removing it can cause a console or GPU to choose a different mode.
Audio is the other. A video preview can look perfect while the capture feed has no game audio because the console is outputting a surround format the card or software does not accept. Elgato’s Xbox setup page specifically directs users to linear PCM for its stated capture path. The broader lesson applies to either card: decide whether the stream needs stereo game audio, party chat, a headset mix, or a separate microphone, then rehearse that route with the actual platform account and OBS scene. A last-minute audio setting is a common way to turn a working capture card into a silent broadcast.
Build the complete capture path before buying
A PCIe capture card decision starts at the source and ends at the viewing display. List the console or camera output format, the monitor’s required refresh rate, the computer’s available slot and lanes, the capture software, the intended recording format, and whether HDR or variable refresh rate actually matters to the viewer. Then reproduce that route with the manufacturer’s current compatibility material open. A card can pass a format to a display without capturing the same combination in the way a creator expects, so “HDMI 2.1” is not a substitute for reading the supported capture and passthrough tables.
Elgato 4K Pro is the stronger candidate when its documented capture formats, software path, and PC requirements line up with a creator’s real game or camera workflow. AVerMedia Live Gamer 4K 2.1 is the better candidate only when its published constraints and the required display path are verified together. Do not buy either card around a maximum-number headline. Run a private rehearsal with the actual console, cable, display, driver, OBS scene collection, and recording settings. Keep one fallback profile at 1080p60 SDR; it is often the quickest way to distinguish a live production problem from a format-negotiation problem.
A practical purchase and rehearsal checklist
Before buying, confirm the available PCIe slot; the exact source and display modes; the desired capture mode; Windows and software support; the destination’s real output target; and the return policy. Before going live, test the highest normal playing mode, the fallback playing mode, HDR-to-SDR handling if relevant, VRR behavior, game and chat audio, a scene change, a local recording, and a full destination stream. Watch both the player display and the program feed. They are allowed to behave differently, but neither should surprise the operator.
The verdict is therefore conditional. Pick Elgato 4K Pro when its published Windows/PCIe, HDMI 2.1 passthrough, and capture limits match a high-refresh desktop workflow. Pick AVerMedia Live Gamer 4K 2.1 when its current manual confirms the same route more cleanly for the gear in hand. If either route depends on an undocumented combination, lower the claim: test before an important show, keep a simpler fallback capture path, and do not promise viewers a mode that the production chain has not proved.
Quick answers
Frequently asked questions
Can I stream at the same resolution that passes through to my monitor?
Not necessarily. Passthrough and capture have separate published limits, and OBS, the encoder, upload, and platform output can impose additional limits. Use the card’s current matrix for the exact source mode.
Is PCIe always better than USB for streaming?
No. PCIe suits a fixed desktop with a suitable slot and a demanding verified signal path. USB can be the better operational choice for portability, laptops, or a simpler route.
Do these cards capture every HDMI source?
No. Both the source’s protection state and the card’s published format support matter. Test with unencrypted video and check HDCP and audio settings before troubleshooting software.