Editing Openai/69676758-d944-8003-a3d4-835e33b4e372 (section)

== gpt-5-mini ==
=== User: How was the cpu/gpu time split determined? ===
How was the cpu/gpu time split determined?

=== Assistant: The CPU/GPU split comes from practical observation, pipeline theory, and the architecture of your target system, not ar… ===
The CPU/GPU split comes from practical observation, pipeline theory, and the architecture of your target system, not arbitrary numbers. Let me break it down clearly.

==== You target 60 FPS → 16.67 ms per frame. ====
This is your hard upper limit for all game logic + rendering.

==== ### ====
* Responsible for: - Game logic - AI - Physics - Animation evaluation - Command buffer submission
* All of this prepares work for the GPU, but cannot execute pixel shaders.

Rule of thumb from real-world engines (Unity, Unreal, proprietary):
* Mid-tier CPU-bound system: ~40–50% of frame budget spent on CPU
* Mid-tier GPU-bound system: ~50–60% on GPU

Why? Because even a “GPU-heavy” frame needs CPU to feed commands and update game state. You cannot ignore the CPU.

For your system (i7-3770K):
* 4 cores, ~3.5 GHz
* Modern GPU is strong (RX 6600 XT)
* CPU becomes the bottleneck first in open-world logic-heavy scenarios → ~7–8 ms for CPU, remaining ~9–10 ms for GPU

This is what I used in the previous table.

===== - Handles pixel processing, shaders, post-processing, draw calls, etc. =====
* A mid-range GPU like the 6600 XT has ~10–12 ms to render a full 1080p frame without stuttering.
* If your frame budget is 16.67 ms, and CPU takes 7–8 ms, GPU can consume ~9–10 ms, leaving a small margin for OS overhead, swapchain, etc.

==== In real engine design, the split is determined by: ====
# Profiling similar hardware / engines - Look at existing games on similar GPUs + CPUs - Identify CPU-heavy and GPU-heavy workloads
# Pipeline theory - Frame time = max(CPU_frame_time, GPU_frame_time) - You can’t push GPU faster than CPU feed rate (CPU becomes limiting), and vice versa
# Hardware knowledge - CPU: limited cores, cache, memory bandwidth → limits AI/physics - GPU: thousands of cores, high memory bandwidth → can handle visuals more comfortably at 1080p
# Safety margin - Always leave ~10–15% frame budget as headroom for spikes, OS overhead, and streaming

===== <syntaxhighlight>Target: 60 FPS → 16.67 ms/frame =====

Estimate CPU-heavy systems take ~45% of budget:
16.67 × 0.45 ≈ 7.5 ms → CPU
16.67 − 7.5 ≈ 9.17 ms → GPU

</syntaxhighlight>
* Then you break CPU/GPU budgets into subsystems (physics, AI, draw calls, shaders) to guide design.

==== Time split is a guideline, not a rule. ====
* You aim for CPU ≤ 7–8 ms, GPU ≤ 10 ms.
* The final profile may shift depending on scene, complexity, and LOD.
* Engines use adaptive techniques to respect these budgets at runtime.

If you want, I can make a diagram showing exactly which parts of the frame go to CPU vs GPU, including game logic, physics, rendering submission, and pixel shading, for your 3770K + 6600 XT target. It’s very illustrative.

=== User: Ok ===
Ok

=== Assistant: Here’s a clear diagram of how a single frame splits between CPU and GPU for your 3770K + RX 6600 XT system targeting 60… ===
Here’s a clear diagram of how a single frame splits between CPU and GPU for your 3770K + RX 6600 XT system targeting 60 FPS (16.67 ms per frame). I’ve kept numbers realistic and rounded slightly for clarity.

===== <syntaxhighlight>┌───────────────────────────────────────────────┐ =====
│ TOTAL FRAME: 16.67 ms                         │
├─────────────┬──────────────┬─────────────────┤
│ CPU         │ GPU          │ Notes           │
├─────────────┼──────────────┼─────────────────┤
│ 7.5 ms      │ 9.2 ms       │ CPU + GPU must run in parallel; frame time is max(CPU, GPU)
└─────────────┴──────────────┴─────────────────┘

</syntaxhighlight>

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===== 1. CPU-limited mechanics - Cap number of active AI/NPCs to fit 3 ms–4 ms total AI + physics per frame. - Spread expensive updates over multiple frames (tick-scheduling). =====
# GPU-limited mechanics - Keep triangle count ≤ ~10–15M on screen. - Avoid >2k × 2 shadow maps per frame. - Limit full-screen post-process passes to ≤ 2 ms.
# Scaling - LOD reduces geometry & animation cost with distance. - Streaming reduces memory footprint; chunk updates amortized over frames.

If you want, I can overlay this diagram with memory/VRAM budgets so you get a full CPU+GPU+RAM/VRAM constraint table for every mechanic on this exact system. That gives a complete “design on paper” blueprint.

=== User: Ok ===
Ok

=== Assistant: Perfect. ===
Perfect. Let’s combine time (CPU/GPU) and space (RAM/VRAM) budgets into a single practical design blueprint for your 3770K + 16 GB RAM + RX 6600 XT system. This gives you a “paper-ready” set of constraints for each game mechanic.

==== - Frame rate: 60 FPS → 16.67 ms/frame ====
* CPU: i7-3770K (4C/8T, ~3.5 GHz)
* System RAM: 16 GB DDR3
* GPU: RX 6600 XT (8 GB VRAM)
* Resolution: 1080p
* Storage: SATA SSD

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Total: CPU ~7.5 ms, GPU ~9.2 ms

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==== When designing each feature, write per-unit budgets: ====

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==== 1. Cap entity counts based on CPU time and RAM usage. ====
# Cap polygon counts & textures based on VRAM and GPU time.
# Spread expensive updates over frames (AI, physics, streaming).
# Use headroom in CPU/GPU budgets to handle spikes.
# Target worst-case scenarios for mechanics, not average.

This gives you a fully constrained design-on-paper template. You can now assign explicit CPU, RAM, and GPU budgets to every mechanic before coding a line.

If you want, I can make a visual “budget map” diagram that shows CPU, GPU, RAM, and VRAM all in one frame—it’s very helpful for quick reference while designing.

=== User: Ok lets look at it the opposite way, how do i calculate the hardware cost of my game design on paper ===
Ok lets look at it the opposite way, how do i calculate the hardware cost of my game design on paper

=== Assistant: Got it — now we’re flipping the problem. ===
Got it — now we’re flipping the problem. Instead of “given hardware, what can my game do,” you want “given a game design, what hardware specs are required to run it at target performance.” This is exactly what studios do for “minimum” and “recommended” specs.

Here’s a step-by-step method.

==== 1. Define your design targets ====

Before estimating hardware, you must know:
* Frame rate → e.g., 60 FPS → 16.67 ms/frame
* Resolution → e.g., 1080p
* Maximum simultaneous entities → NPCs, physics objects, particles
* Maximum texture & geometry fidelity → polygons, texture resolution
* Maximum post-processing effects → shadows, lighting, screen-space effects

: These numbers are the design inputs for the calculation.

==== 2. Estimate CPU cost per mechanic ====

For each system, estimate time per unit per frame.

| Mechanic          | CPU per unit (ms) | Units | Total CPU (ms/frame) |
| ----------------- | ----------------- | ----- | -------------------- |
| NPC AI            | 0.025             | 100   | 2.5                  |
| Physics body      | 0.002             | 500   | 1.0                  |
| Animation eval    | 0.010             | 150   | 1.5                  |
| Game logic        | –                 | –     | 1.0                  |
| Scripting / audio | –                 | –     | 0.5                  |

Sum → CPU time per frame
Example: 6.5 ms → required CPU must have at least this much per core (or multi-threaded equivalent).

==== 3. Estimate GPU cost per mechanic ====

Same approach, but in GPU milliseconds or complexity units:

| Mechanic                     | GPU cost per unit | Units | Total GPU cost |
| ---------------------------- | ----------------- | ----- | -------------- |
| Character geometry & shading | 0.05 ms           | 50    | 2.5 ms         |
| Environment props            | 0.005 ms          | 500   | 2.5 ms         |
| Particles                    | 0.01 ms           | 200   | 2.0 ms         |
| Post-processing              | –                 | –     | 2.0 ms         |
| Shadows                      | –                 | –     | 1.0 ms         |

Sum → GPU frame time
Example: 10 ms → GPU must be able to execute that workload in ≤ 10 ms at the target resolution.

==== 4. Convert CPU/GPU time to hardware class ====

Once you have total CPU & GPU time per frame:
# CPU: ``<code> Required CPU performance = total CPU workload / frame time per core </code>`` - Adjust for multithreading and per-core efficiency. - Use benchmark numbers of real CPUs: - e.g., if your design uses 6.5 ms CPU per frame on one “simulation” core, a CPU like i7-3770K (~3.5 GHz) can handle it. If >10 ms, need a stronger CPU.
# GPU: - Convert total GPU ms → GPU throughput needed: - Vertex throughput (Mvertices/s) - Pixel throughput (MPixels/s) - Shader performance (GFlops) - Compare to benchmarked GPUs. - Example: total shading cost = 10 ms at 1080p → 6600 XT class can handle it. 4K would need stronger GPU.

==== 5. Estimate memory requirements ====

===== RAM =====
# Sum all gameplay, physics, AI, audio, streaming buffers.
# Add OS overhead (3–4 GB for modern Windows).
# Add safety margin (~10–15%).

Example: design requires 8 GB + 4 GB OS + 10% → 13.2 GB → recommend 16 GB RAM minimum.

===== VRAM =====
# Sum all textures, geometry buffers, render targets, shadows, post effects.
# Add headroom (0.5–1 GB).
# Example: 6 GB total → recommend 8 GB GPU.

==== 6. Factor in bandwidth ====
* CPU: RAM bandwidth may limit AI/physics-heavy systems.
* GPU: Memory bandwidth may limit high-resolution textures or full-screen effects.
* Include headroom (~10–20%) in both cases.

==== 7. Define minimum / recommended / high-end specs ====
* Minimum → can just hit your frame target at lowest settings.
* Recommended → comfortable frame rate, medium-high settings.
* High-end → maxed-out settings, higher resolution / FPS.

| Tier        | CPU                 | RAM      | GPU                     | Notes              |
| ----------- | ------------------- | -------- | ----------------------- | ------------------ |
| Minimum     | ~i5/i7 3rd gen      | 16 GB    | 6600 XT / GTX 1060      | 1080p 60 FPS       |
| Recommended | 6–8 cores, 3.5 GHz+ | 16–32 GB | RTX 3060 / 6600 XT high | 1080p Ultra 60 FPS |
| High-end    | 8+ cores            | 32 GB    | RTX 4070+ / 6800 XT     | 1440p 60–120 FPS   |

===== ✅ Key principle =====
* Start with frame budget and mechanics cost.
* Sum per-unit costs to get total CPU/GPU time and memory.
* Compare to benchmarked hardware → pick hardware tier.
* Iterate: tweak mechanic complexity or entity counts until budget fits desired tier.

If you want, I can make a worked example calculation for one specific system, like your 3770K + 6600 XT, showing exactly how to calculate minimum CPU cores, GPU power, RAM, and VRAM from a hypothetical open-world game design. That turns theory into a step-by-step “on-paper hardware calculator.”