ratio of heat generated by the CPU and GPU versus the heat generated by PCIe devices that would be controlled by ASPM

[http://dummy.us.eu.org/robert (Robert)]

There is no single fixed ratio because it depends entirely on the workload
(idle vs. gaming vs. rendering) and the specific hardware (integrated
graphics vs. discrete GPU, high-end CPU vs. low-power mobile chip).

However, we can estimate the ratios based on typical power consumption
profiles, since Heat ≈ Power Consumption.

1. The General Rule of Thumb

In a typical desktop or laptop system:

CPU + GPU: Account for 80% to 95% of total system heat.
Motherboard/Chipset/PCIe Devices: Account for 5% to 20% of total system heat.
ASPM only affects the PCIe portion. Therefore, even if ASPM reduces the
heat of PCIe devices by 50%, the impact on the total system heat is
relatively small.

2. Scenario Breakdown

A. Idle / Light Workload (Web browsing, text editing)
CPU: ~5W – 15W
GPU: ~5W – 10W (if integrated) or ~10W – 20W (if
discrete, even at idle) Total CPU+GPU: ~10W – 35W
PCIe Devices (NVMe, WiFi, USB controllers): ~2W – 5W total
ASPM Impact: Without ASPM, these might draw 4W–6W. With ASPM, they drop to 1W–2W.
Ratio:
CPU/GPU Heat: ~85%
PCIe Heat: ~15%
Conclusion: ASPM saves maybe 1–2 Watts out of a 20W total system draw. The heat reduction is barely noticeable to the touch but helps battery life.

B. Heavy Load (Gaming, Video Rendering, AI Training)
CPU: ~65W – 150W+
GPU: ~150W – 450W+
Total CPU+GPU: ~250W – 600W+
PCIe Devices: ~5W – 10W (They are running at full speed, so
ASPM is disabled by the hardware because the link is busy).
ASPM Impact: Zero. When the GPU is rendering a game, the PCIe link is in L0 (active) 100% of the time. ASPM cannot put it to sleep.
Ratio:
CPU/GPU Heat: ~98%
PCIe Heat: ~2%
Conclusion: ASPM has absolutely no effect on heat during heavy loads.

C. Mixed/Background Load (Downloads, compiling code, server idle)
CPU: ~20W – 50W
GPU: ~10W – 30W
PCIe Devices: ~3W – 8W (Network cards and drives might be
active intermittently).
ASPM Impact: Can save ~1W–3W during gaps in activity.
Ratio:
CPU/GPU Heat: ~90%
PCIe Heat: ~10%

3. Visualizing the Heat Distribution

Component Category	Typical Power (Idle)	Typical Power (Load)	% of Total Heat (Idle)	% of Total Heat (Load)	ASPM Effective?
CPU	5–15W	65–150W+	~40%	~20%	No
GPU	5–20W	150–450W+	~40%	~70%	No
Motherboard VRMs/Chipset	2–5W	5–15W	~10%	~5%	Indirectly
PCIe Devices (SSD, NIC, etc.)	2–5W	5–10W	~10%	~5%	Yes (Idle only)
Total System	~20W	~600W+	100%	100%	
(Note: Percentages vary based on hardware efficiency and specific components.)

4. Why the Ratio Matters for Your Decision
If your goal is to lower the temperature of the CPU or GPU to prevent
throttling:

ASPM will not help. The CPU and GPU generate their own heat based on their
voltage and frequency. They are not cooled by the PCIe link state.

The only way to cool the CPU/GPU is better airflow, better cooling
solutions, or undervolting.

If your goal is to reduce overall system heat (e.g., to keep a small
form-factor PC or laptop cooler):

Suspend is the winner. As discussed, suspending drops the entire system
(CPU+GPU+PCIe) to ~2W.
ASPM is a minor player. It only trims the "tail" of the power curve.

Summary
The ratio of heat generated by CPU+GPU versus ASPM-controlled devices is
roughly 9:1 during idle and 20:1 (or higher) during load.

CPU/GPU: The "Main Engine" of heat.
PCIe/ASPM: The "Accessory" heat.
Fixing your suspend issue (which shuts down the Main Engine) will reduce
heat by orders of magnitude compared to tweaking ASPM (which only tweaks
the Accessories).