CPU overclocking is totally different case. It crash if some inside databus data is wrong becouse parallel digital data is not qualid exactly this time when it need be. (I do not explain all things, it is extremely complex to explain with bad english. There is also many other problems as temperature. Hot spots inside chip and also many wear and tear things on the chip.)
This AD's ADC is "100 MHz" chip, if it is labeled -40, -80 or -100. This chip digital parts work very easy with 100MHz without any digital data qualid problems inside chip. Indirectly this can read also datasheet. Also this kind of company as Rigol (no 1. or 2. in world for manufacturing oscilloscopes. They make also OEM). They can do all specifications tests for chips just same quality (or more) than chip manufacturer. (yes I wait time when Rigol co to they own chip designs or even manufacturing as HP or Tektronix before)
Also they can order standard chips with they own label. If they do this nobody tell any overclocking becouse nobody can not see any overclocking problems)
This "overclocking" what is not really overclocking in normal "CPU or Memory" meaning. And also not as PCB overclocking. Yes there is many times problems becouse PCB RF design is not good or not good for overclocking and bus timing may also fail there. 100ps is long time and travel distance on the PCB trip may be 20mm (trivial example) and more complex it go with strip lines becouse there is resistance capacitance and inductance. Also transmitting part have these and receiver chip.
CPU itself or whole system overclocking is totally different case and it may affect component lifetime and system reliability.
But what happend if put -40 ADC (what is really same chip as -100 chip). It works fine and without problem in most case in digital side. No corrupted data no timing problem what can conflict with data reading chips.
Problem is in ADConversion. (in most case) And if problem is other type these cips come not out from AD. If there still are chips what fails with 100M they can test out before go to scope PCB. After scope PCB is ready and if there is "bad" chips they fails and do not go to customers. (just as all do..., Nokia, Tektronix, Agilent etc)
Interesting part of this case is Analog Digital Conversion (ADC) itself quality.
-40 Chip do not reach same ADC quality as -100chip with 100MSPS. -100 chip ADC quality you can read directly from datasheet and this AD quarantee. (example around 7bit total accuracy or littlebit worse. Dynamic perfomance part of datasheet is meaningful and I "quess" there these -40 chips used as -100 chips do not reach same quality at all. SINAD/SNR and harmonic distortion may differ lot of.
But now it is important to understand that we do not look ADC specs. They are not promised Rigol scope specs.
Rigol do NOT promise even nearly same for oscilloscope.
Inside scope specs "window" +-4% or +-3% is lot of room for bad and poor ADC. Only they tell that still ADC resolution is 8bit. Yes it is, it can product to databus 8 bit bytes. But real accuracy is nearly as 4 or 5 bits. +-4% window have lot of room for also these things what come from ADC. (encode pulse timing is too short for this -40 labeled chip if we think what conversion quality is promised if it is used with more slow encode signal.)
This is quessing. Most reasons for -40 label on originally -100 designed and producted chip is inside anlog channel and S&H complex ("bad silicon" ... but maybe there can find also more selective and accurate explanation. Strip lines and components quality in analog part and capacitor and switch (sampling) components. More fast run more lost in analog and conversion accuracy there. And Rigol do NOT promise accuracy what can do with -100 chips. (but also Instek do not promise
But what do Instek.
They overclock. Chip is 100M chip (also this -40 chip) and digital parts (databus and timing there) is quaranteed with chip design for this speed. Instek go over this! Rigol do not go over this. Going over this limit is more danger (but Instek go only littlebit (125/100) and maybe this do not make also any problem aspecially if (data etc) timing outside of chip is good (also need remember that specs data are made for 3.0Vdd but chip normal use area go up to 3.6V (not as abs max).
Rigol go over analog specs. Instek go over chip designed digital speed. What happend if data is not qualid. It can be random 8 bits. In Rigol case there is more like only analog conversion itself quality problem if compare to datasheet quality promises. (and these Rigol do not promise.) Rigol promise DC aacuracy +-3 to +-4%. (these limits includes also ADC conversion itself error. Btw 8% from 255 is 20,4. 4bit is 16.
So there is huge room also for ADC origin error. Wery easy can drop one bit out and after it we can accept -40 chip used as -100 chip but specs read not now signal to noise ratio 44dB or differential nonlinearity typical +-0.5LSB)
If there happend some other "mystified" things as they do "overclocking" I am very interested to find any mystified problem origin from this "overclocking".
Yes I know lot of stability problem and crashed computers. But please do not compare these if you really do not know AND understand theoretical and practical difference to this case.
Rigol, Instek and others they sell oscilloscopes and they have published specs for they product. I buy oscilloscope not ADC chips. If Oscilloscope specs meet my needs and I believe quality is ok and price... yes of course I sometimes want buy also name.
One but small scope manufacturer in world is Tektronix. But in the "golden years" it have good name specially with scopes. Yes there are maybe also some reasons for this thinking about "good" with this name but... in the truth.. they have made many many bad designs and bad production but I do not have pictures about extremely bad "hop wires" and bad solderings and bad designs and specially bad component selections.
More difficult is "overclocking" but you can not know it becouse chips are Tektronix design and tektronic manufacturing.
How peoples can buy oscilloscopes what are made with components "no datasheet".
What is designed durability. 10000hr? (what you think about 500MHz vertical amplifier hybrid chipa (this case mixed digital and analog) where case temperature in normal use is more than 90 celsius in normal room temperature.
Yes you can buy these Tektronix good brand oscilloscopes in ebay. Very typical is that seller put picture where scope is power off. "we have no knowledge or possible to test"...hehe)
I have never understand this big mouth talking about "overclocking".
There is only clever engineers who find this solution. There is also lot of power for testing.
But where are these units what have real problems. I have use lot of time for surfing internet and find anything but only peoples self made fails. Where are these reliability problems. Scope have sell lot of and long time. Where are these bad solderings errors and ADC fails becouse "overclocking" ... I have seen lot of Intel and AMD crashed with overclocking... burned CPUs burned display drivers etc and etc. But I have not seen or heard any crashed ADC or burned ADC about Rigol. Mybe there are fails... of course there are normal fails but if this is any kind of problem there is full of internet talking it. How many they have sell total DS1052E and 1102E?
I hope some specialist (who also really know) write with better english also this kind of things what are in theoretical and practical things related to this kind of using AD9288 out of its specification sheet.
But my tight opinion with my all knowledge is that comparing to CPU's and this kind of overclocking is not relevant.