Build in stages

The recommendation

Keep the 9900K platform for now. Improve the parts that can move into the next build, then shop a complete used AM5 platform when the price is right. The 9900K is already near the top of Z390; another CPU for that board will not produce the transformation you want.

For a substantial work-first CPU upgrade, my value candidate is a used Ryzen 9 7950X. For a bigger combined gaming and workstation budget, it is the 9950X3D. Both require an AM5 board and DDR5. The benefit depends on the job; we have not measured either in this fleet.

A gaming CPU will not remove an RTX 3060 graphics limit. A faster CPU will not accelerate the remote model behind a cloud-agent API. Local builds, exports, tools, and local model inference each need their own comparison.

Spend where the benefit is clear

First preserve the music, then measure the job you want to improve. Cooler spending buys potential thermal or acoustic headroom; GPU and CPU spending address different throughput limits. Rehousing buys space. A PSU supports the selected hardware and is not the default first purchase.

╔══════════════════════════════╗
║ PRESERVE MUSIC FIRST         ║
╚══════════════════════════════╝
   ║ copies + restore checks
   ▼
┌──────────────────────────────┐
│ KEEP THE FLEET / $0 new gear │
└──────────────────────────────┘
   Mini / Air / Yard: reuse
   Desktop: 9900K + RTX 3060
   Omarchy: light Linux work

WHAT NEEDS TO IMPROVE?
├┈ Cooling or noise
│  Value air: PA120 Mini
│  $35–50 buying allowance
│  alt: NH-D12L $100–120
│  alt: Arctic 360 $110–160*
│  Choose ONE CPU cooler
├┈ Case airflow or fan noise
│  Keep current fans: $0
│  alt: P12 Pro PST 5-pack
│  $30–45 allowance if needed
├┈ GPU-limited games / compute
│  Used 4070 Ti SUPER 16 GB
│  Wait for ≤$700 target
├┈ CPU-limited work
│  Used 7950X+B650+64 GB
│  Wait for ≤$850 set target
├┈ New GPU needs another PSU
│  Confirm existing model
│  RM850x: $169.99 quote
└┈ Smaller footprint
   Used D41 Mesh: $50–80
   Space benefit; no speedup

┌──────────────────────────────┐
│ WINTER / ORIGINAL INTEL LAB  │
└──────────────────────────────┘
   RX 5600 XT + OpenCore
   Image / kexts / benchmarks

Dotted paths = optional choices.
*AIO + socket-kit allowance.
USD; targets are not offers.

All figures USD before tax/shipping unless specified. Allowances are spending plans; targets are buy thresholds; MSRP is a reference; earlier quotes require rechecking. No measured FPS-per-dollar or cooling-per-dollar comparison exists for these upgrades.

Cooling: cost versus benefit

Cost/value changes the first cooler to price: Thermalright Peerless Assassin 120 Mini. The NH-D12L remains the premium compact-air choice. Neither has been tested on this desktop, so these are fit-and-budget recommendations, not a measured ranking of degrees per dollar.

The PA120 Mini has a 135 mm heatsink and supports LGA115X/AM5. The NH-D12L is 145 mm with its fan. The original O11 Dynamic permits 155 mm CPU coolers. A raised fan can consume clearance; check installed dimensions before ordering.

Arctic Liquid Freezer III Pro 360 is the liquid candidate that can span the current Intel platform and AM5. Budget $110–160 including a socket-kit allowance; local retail is unverified. Its thick radiator/fan assembly needs at least 63 mm clearance, plus tube, motherboard and cable room. Arctic’s LGA1200/115X kit supports the 9900K socket; confirm box revision and whether the kit must be purchased separately. Buy one CPU cooler, not air now plus liquid immediately afterward.

For liquid, the intended layout is top radiator exhaust with existing bottom/side fans supplying intake, subject to fit and actual fan placement. Keep the included radiator fans. Air cooling avoids pump maintenance; a 360 mm radiator offers more heat-rejection area for sustained work, with added installation and pump complexity. Neither guarantees silence or a specific temperature drop.

Case-fan choices: Arctic P12 Pro PST for value; Noctua NF-A12x25 G2 PWM for premium refinement. The Noctua launch MSRP was $34.90 each, not a verified checkout price. Existing fan RPM readings alone cannot establish airflow or acoustic quality. Test the chosen CPU cooler first, then spend on case fans only if a problem remains.

All fans are already Full Speed. The 85°C campaign cutoff was our policy, not evidence of a defective cooler or PSU. More FPS is possible only if cooling removes an actual thermal constraint; none has been demonstrated here. Compare identical load, room conditions, power, temperatures, clocks and noise after one change.

Purchase links and price checks

Lowest readable offers found, not a guarantee of the lowest checkout total. Checked September 6–7, 2026. USD before tax; shipping noted where shown. Seller pages can be cached. Unverified, historical and out-of-stock entries are labeled explicitly. Alternatives are not a single cart.

Best concrete lower-cost cooling offer found: the $79.99 Arctic AIO. For the current machine, its mounting-kit availability and total fit still decide whether it is practical. The $49.99 PA120 Mini remains the simpler air option. Buy one cooler, then rerun the same guarded test; case fans remain optional.

What to shop, and when

First spending decision: no purchase if present noise and real workloads are acceptable; otherwise price one fitting CPU cooler. The value-air allowance is $35–50. PSU, case fans and enclosure remain separate conditional decisions. See the cost/value table above for mutually exclusive cooling budgets.

A later used platform at our $850 ceiling plus a $700 GPU ceiling and the PSU totals $1,719.99, excluding cooling, enclosure, storage, tax and OS licensing. This is a spending envelope spread across stages, not proof those deals exist.

Corsair RM850x quote and specifications. Use only the new PSU’s supplied cables. The historical SolidGear receipt does not confirm the currently installed unit or establish a PSU fault.

The whole configuration

64 GB is the target; 32 GB is a capacity reduction from your present 48 GB. Use two matched DIMMs, start at supported default speed, and treat DDR5-6000 EXPO as a later tested setting. Do not move the old DDR4 into AM5 or assume four populated slots will hold the same speed.

MSI B650 Tomahawk specifications list Ryzen 7000/9000 support, ATX size, 2.5 Gb Ethernet and three M.2 slots. Verify the exact CPU support list and installed BIOS before buying. Its second long slot is only ×2 electrically, so this is a single-primary-GPU recommendation.

Where used makes sense

• CPU and RAM: good candidates when tested together with a return path. A used 7950X seller page showed $349.99; search results also showed lower asks. Seller claims are not our validation. Cheap CPU pricing alone does not make the full DDR5 platform cheap.
• GPU: compare exact working cards, not parts-only listings or live auction bids. A 4070 Ti SUPER sold for $620 in June; that is a historical example, not current availability. September asks checked were higher. Seek clear photos, exact model, return terms, and a demonstrable memory/render test.
• Case and air heatsink: useful savings if all brackets, standoffs, filters and screws are present. Buy locally if shipping consumes the saving.
• PSU, backup drive and liquid cooler: I prefer new for this build. Unknown cable sets, drive history and pump age are poor places to trade certainty for a small discount.
• RTX 3090: consider only if a specific local AI workload needs its 24 GB VRAM and accepts its 350 W board-power class. It is not my default gaming upgrade. A refurbished seller example at $1,499 was poor value for this plan; do not assume the old $600–700 bargains still exist.

A smaller box without wasting the board

The Jonsbo D41 Mesh accepts your ATX motherboard. Its stated chassis volume is 35.4 L; its full external dimensions are 205 × 407 × 452 mm. It is compact ATX, not a tiny ITX build. Its CPU-cooler allowance is 168 mm, compared with 155 mm for the original O11 Dynamic.

Cheapest: keep the O11. Smallest sensible reuse: move the existing platform into D41. Two systems later: put the Intel/Radeon lab in D41 and the new AM5/NVIDIA platform in O11. That last option needs another PSU and storage; do it only if the second computer earns its upkeep.

Check Jonsbo’s PSU/radiator/GPU placement table: allowed GPU length changes with PSU position and radiator size. Confirm the exact card, cable bend clearance, drives and fan placement; do not add each headline maximum independently.

Choose the enclosure before committing to liquid cooling. The cooling comparison above covers height, radiator thickness and socket-kit requirements. The earlier Nautilus 360 suggestion remains AM5-only in this plan; the Arctic option can serve the current LGA1151 CPU with its proper kit.

All fans are already Full Speed. Our 85°C stop policy did not diagnose inadequate cooling. A cooler purchase is for desired noise and load headroom, with a matched workload measured before and after.

Give each GPU a clear job

Dortania lists RX 5600 XT support; that is a compatibility starting point, not proof of this exact EFI/macOS combination. RTX 3060 is unsupported in macOS. The Radeon therefore has a useful lab role while your actual Macs remain the everyday macOS machines.

The M4 Mini and Air do not provide a supported home for it as an eGPU: Apple’s eGPU support requires an Intel Mac. Yard is a cloud server; it can send work to a local GPU worker over the network, but cannot accept this physical card.

A future MSI 5070 Ti Ventus 3X OC reference model is 303 × 121 × 49 mm and 300 W, with 750 W recommended system PSU. The proposed 850 W unit provides room for the CPU configuration. Verify the exact retail suffix and connector clearance before selecting any card. There is no verified live GPU offer included in this shopping cart.

Music first, starting with discovery

The first bounded private inventory passes are complete. Actual cloud audio and project data were observed, but copies and restore verification are still pending; no scanner is currently running. The earlier disk audit found the old APFS partition and OpenCore files; it did not inventory the macOS volume. No claim that the music is backed up follows from finding that partition.

1. Inventory every source

   Logic packages and legacy projects; alternatives and automatic backups; separate audio folders, unused takes, sampler files, MIDI, presets, other DAW sessions, and ZIP archives. Search personal OneDrive and Google Drive with account and pagination coverage recorded. A cloud-sync placeholder is not a downloaded copy.

2. Copy before touching the installation

   Keep the source disk intact. Choose storage with room, copy complete project structures with metadata, compare file counts and hashes, and make a second independent copy. Do not initialize an unreadable APFS disk in Windows. Missing access is a gap to solve, not an empty-volume result.

3. Prove the songs can be recovered

   Work on copies. Logic’s Consolidate command gathers supported external assets. Preserve alternatives and unused source material separately too. Check missing-media and plugin warnings, render stems/reference mixes where old plugins still work, and test with the original disk unavailable. A project file alone may not contain the performance.

File and account details stay private. Inventory, copied files, verified hashes and a successful restore are separate milestones. The full system image is deferred; targeted music preservation should not wait for winter.

A useful OpenCore contribution

Keep the original Intel platform together until its behavior is captured. On the winter session: preserve the full disk and exact original EFI privately, then benchmark a working copy. Record BIOS and macOS builds, OpenCore version, kext versions and hashes, ACPI, boot arguments, loaded extensions, USB mapping and exact GPU identity.

Cover CPU and Metal workloads, hardware encode/decode, Logic low-buffer playback and bounce, interface/USB behavior, sleep/wake and sustained load. Use fixed fixtures, repeated runs, frame times or completion time, error logs and temperatures. Vary one kext/config setting at a time; report failed runs and guards along with successes.

Prepare a shareable dossier with synthetic audio and a sanitized EFI/config comparison. Strip serials, MLB, ROM, UUIDs, network identifiers and personal paths from public copies; preserve the exact original separately. Dortania debugging documentation and the OpenCore configuration reference guide the evidence capture. Posting to community threads remains a later explicit action.

Before ordering or rebuilding

Confirm the monitor resolution/refresh, target games and real working set; exact PSU label; GPU dimensions; complete CPU/board/RAM price; backup destination and recovery coverage. Install a new OS with the original music disk disconnected. Start the new platform at stock/default settings, then qualify memory and performance in stages. Keep old parts until the fallback and music recovery are proven.

Return to all measured fleet results. Prices were researched during the September 6–7 session, exclude tax unless stated, and require rechecking. Manufacturer specifications establish compatibility limits; proposed component choices and buying ceilings are engineering judgment, not promised speedups.