That is not an old adage and where did you get that 5% value? Got a link?
Yes, I provided a link to a post which has all the data .... you just chose not to read it before responding. If your going to reply to a post, please read it 1st, including the links, and confine the responses to the subjects / technology actually referenced in the post ... there was no mention of any user built, home built, slim, Asus or MSI notebooks, yet this is the entire basis of your counterpoint. Im sure you are familiar that there exists "custom desktop builders" out there like Cyberpower where one can choose case, MoB CPU, GPU... yada yada yada and get a 'custom built PC" ... It was my understanding that folks could give you a list of parts and you would build them a "custom built PC" . I assume you would advise your user if the CPU / Case cooling system they selected was inadequate for their chosen componentry. The fact that you are unaware of the similar existence of a "custom laptop industry" is, well, surprising.
I never mentioned any teeny chassis laptop, only custom built. So the examples you gave with teeny chassis, MSI, Asusetc. are non-reponsive. Back in the day you could easily buy a laptop with desktop CPU / GPU ... even SLI'd GPUS. SLI lappies not as widely available today but you still can buy desktop components in a laptop chassis ... I had one custom Clevo build in the post you didn't read. Even today, your looking at almost 9 pounds for the ones housing desktop componentry. The cooling systems were and still today are custom designed to handle the applicable loads. After all these years, never had a cooling system issue....and I have run Furmark / RoG Realbench on all of them. If your experience is limited to slim, MSI / Asus factory built laptops ... how can you speak to the subject which specifically excludes any such consideration ?
If you are unaware of, or have you never opened a custom built laptop, I don't see how you are in any position to comment on how difficult they are to clean. You are also under the mistaken impression that you can't swap componentry. We are talking standard chassis designs here. There's really not that much involved ... remove about 7 teeny screws, remove the back cover, and turn on the air compressor . Just hold finger on the fans as yoiu can break them by overspinning. Did that once, replaced it. I have also swapped out GPUs, HDs, SSHDs, SSDs, memory... hardest swap was the CMOS battery. The cooling systems are massive, all copper with multiple fans and a manual "turn all fans on max" key combo. None of this exists in the realm of which you decribed but it does exist.
Returning to the now familiar theme of mistaken assumptions, the only thing misleading about "custom built" laptops is your mistaken assumption of what "custom built" means There was no mention of home built, user built or self built..... the words used were "custom built". Here's a link
built to individual specifications… See the full definition
www.merriam-webster.com
Definition: "built to individual specifications"
There's no need for an elaborate / imaginary parts search scenario which you described. Apparently without your knowledge, a custom built laptop industry has existed for over 10 years. Its far from uncommon to see folks parrotting what they read on a website 8 years ago. Alienware, which opened in 1996 ... was probably the most well known provider and offered custom built desktops and notebooks for sale to the general public. Others included EuroCom, FalconNorthwest, Widow PC, XoticPC, ProStar, LPCdigital and others. Most of them get their chassis parts from Clevo ... if you had looked at the 2nd link in the previous post, how this industry operates would have been quite clear....
"Clevo is a Taiwanese manufacturer that creates barebones notebook chassis for other OEMs to fill in with the necessary specific hardware components, providing materials for companies like HP and Lenovo/IBM to put their finishing touches upon. A little known fact is that Alienware used to be a Clevo reseller until they became so profitable that they were bought out by Dell.
So here's how this works .....
1. Select Barebones Chassis a) 13-14" b) 15-16" c) 17" d) Workstations
2. Choose desktop componentry (i.e. 9900k) or mobile componentry
3. Choose CPU
4. Choose screen type / resolution
5. Choose options, dead pixel warranty, screen calibration
6. Choose GPU
7. Choose memory configuration
8. Choose OS or pick none
9. Choose thermal compound
10. Choose M.2 RAID options
11. Choose SSD 1
12. Choose SSD 2
13. Choose SSHD / HDD 1
14. Choose SSHD / HD 2
15. Choose M.2 RAID options
16. Choose Wireless / Bluetooth options
17. Choose Extended warrantees
18. Chose Express shipping if desired
19. Choose other accessories
20. Choose bag
Few days later, a laptop, "
custom built to your specifications" arrives at your door step. Some vendors even offer custom splash screens, decals, paint jobs and other options
And, no ... I wouldn't attempt to put a buy a MSI notebook and swap in an ASUS graphics card because neithr Asus nor MSI make custom built laptops. Asus doesn't even ***make*** a single laptop. And yes, I have swapped GPUs, CPUs, HDs, SSDs, SSHDs, and RAM ... Remember... all these "custom built laptops" start with a chassis ONLY.
You asked for a link that was there ... you misstated what "custom built" means ... you were unaware of a custom built laptop industry and, as to the Hogwash, ya really should have clicked that link, the numbers don't lie. Here's some of the data you would have seen if you clicked it the link in original post
Was a time when buying a laptop meant significant drop in performance ... those days have gone the way of the VCR and Blockbuster. It's a new era and it's been here for quite some time. Unfortunately folks are still parroting web site posts from a decade ago referring to a world we no longer live in.
https://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html
The 5th ranked GPU listed in the GTX 2080 (Desktop) - Performance Rating = 76.7 ... 5% faster than the mobile version
The 8th ranked GPU listed in the GTX 2080 (Mobile) - Performance Rating = 72.8
The 2080 Desktop has the following 3D Mark Scores = 436117 / 143576 / 27620 / 40278
The 2080Laptop has the following 3D Mark Scores = 449825 / 139346 / 25440 / 35035
3D Mark Ice Storm = +3% difference
3D Mark Cloud Gate = -3% difference
3D Mark Firestrike = -8% difference
3D Mark 11P = -15% difference
Would seem that te quote "Today's lappies lose as little as 5% to their desktop counterparts" needs revising ... shuda said "loses as little as 3% ... average was 5.75% in the four 3D Mark Tests
From there you can link to the game scores by clicking on the "Gaming Performance List" link ... again from the original link
Here are game scores as tested 1920 x 1080 High Preset ..... Game = 2080 Desktop Score (D) / 2080 Laptop Score (L)
Star Wars Jedi Fallen Order = 102 D / 117 L (+15%)
Need for Speed Heat = 124 D / 118 (-5%)
CoD Modern Warfare (2019) = 178 D / 168 L (-6%)
Grid (2019) = 140 D / 144 L (+3%)
Anno 1800 = 77 D / 76.8 L (< 0.5%)
Metro Exodus = 87.9 D / 86.9 L (-1%)
Far Cry New Dawn = 102 D / 105.5 L (+3%)
Shadow of the Tomb Raider - 117 D / 113 L (-4%)
Rocket League = 242.5 D / 248.0 L (+2%)
Based upon those numbers ... it would appear the "old adage" is exactly that. Still, we do have the "In real life" issue to deal with as to obtaining comparable test data . Outside of notebookcheck site, it's hard to find apples and apples numbers. How many laptop / desktop tests have you seen with both having a 9600k / 9700k or 9900k ? Same storage systems ? ... same chipset ? Which mobile GPU was used in the test ... the mobile 2080, the 2080 Qmax (90 watt) or the 2080 Qmax 80 watt ?
That's the thing... if you take the simplistic approach, comparing apples and strawberries ... you can compare some Asus design with a custom build top end box that doesn't give a care to battery life .... what is the 9900k / 2080 desktop being compared with ?
Are we talking 9900k, 9700k, 9600k, 9980 HK, 9750H, i5-9300H
Are we talking Z370 Chipset or HM370chipset ?
Are we talking mobile 2080 (150 watt), 2080 Q-max 90 watt TDP or 80 watt Q-max ... just about all store boughts are Q-max designs
Are we talking same storage subsystems ?
And that's the other issue ... in the typical desktop versus mobile testing. I have seen differenbces in single digit % differences...n I have also seen them break into the low 30s. The one in the 30s however, are usually well up over 90 / 100 fps where much of the gain is coming from the CPU. How much impact does that have on the store boghts 60 hz screen ?
So link to as many store bought test results as you can find, but unless they are apples and apples" it is irrelevant. The mobile 2080 has a 1380 Mhz base clock... the Q-max design is only 735. So yes, your store bought Asus / MSI may just apply to that old adage, tho no where near as much as it once did. But the subject of the post is limited to custom builts who are not limited to MaxQ designs ... and are therefore running at a base clock 88% faster than the mobile benchmarks you are looking at. The mobile 2080 clocks 92% as fast as the desktop version. If battery life is a concern, opt for the Qmax and take the performance hit. Personally, we almost never use our lappie on battery ... maybe when I need to look up a phone number or send a file, that's it.