What would the difference between 1.5 and 1.6v athlons be?

[CTho9305]

What is the difference between a 1.5v and a 1.6v tbred-b? If they clocked higher at 1.6v, wouldn't it make more sense for AMD to sell them that way for more money? Are they different enough that they don't last as long at 1.6v? I'm asking here because I'm hoping to get an answer that is more technical than the "because AMD says so" or "so we can overclock them" answer I'd get in CPU/Overclocking.

edit: They are both manufactured on a .13u process, right?

 

1. Put simply, the 1.5 V cpu's need less power to work at a higher speed. Something was redesigned I have no clue what but that was the end result.

2. I have heard that AMD is going to discontinue some of their slower XP's, probably becuase they can perform so much better than for what they are rated. Remember also that new chip designs are not so common. The difference between a 1700 + and 2100+ is not hardware. All chips start out the same and then are sorted based on how good they are (the manufacturing proccess isn't perfect) and based on the demand (more people want midrange chips) . They are then programed to go at x mhz and sold. If all were sold at the fastest speed then prices would drop for fast proccssors and few slow proccessors would be available. End result would be alot less income for AMD because people with little money would have no choices and everybody else would be spending the same amount instead of as much as they could afford.

3. AMD wants the proccesors to run very stably at stock settings, and 1.5V translates into less power and heat. (power as in P=IV) Often when overclocking people do raise the voltage in the hopes that it will enable the cpu to reach higher speeds but AMD does not overclock because this greatly reduces the reliability of a chip. Note that overclockers look for CPU temps of like 45 degrees C while AMD says that the CPU's are garanteed up to someting like 85 degrees C.

 

[CTho9305]

That wasn't the type of answer I was looking for... but someone in the field thinks it might have been a small process shrink (e.g. less than going from .13u to .09u, but maybe from .13u to .125u) meaning that the 1.6V could now be too much for a long part lifetime, so I have an answer

 

nm, I'm rereading them and i think i might be wrong but i'll keep them posted cause they make a nice read anyway





here are the data sheets:

AMD Athlon XP Processor Model 6 Data Sheet
AMD Athlon XP Processor Model 8 Data Sheet
AMD Athlon XP Processor Model 10 Data Sheet

 

[Lynx516]

Originally posted by: CTho9305
That wasn't the type of answer I was looking for... but someone in the field thinks it might have been a small process shrink (e.g. less than going from .13u to .09u, but maybe from .13u to .125u) meaning that the 1.6V could now be too much for a long part lifetime, so I have an answer

I find that highly unlikly concidering the cost of changing prossesses is in the order of a billion dollars. I would say that they are binned that way. and as AMD have a stock excess they are selling them at any speed they go at. Just that 1.5v ones do so at a lower voltage therefore running cooler

 

[sgtroyer]

It's not likely to be a reliability concern. The two consequences of running at higher voltage are higher power dissipation and shorter part life. However, if AMD determined that a faster part can take 1.65V, then there's no reason a slower part can only take 1.5V. Remember, they're exactly the same design. It would be safe to give a slower part 1.65V, but if 1.5V is enough to run at speed without errors, why give more? Power dissipation goes up with the square of the voltage, and cooling costs money. AMD wants to provide the cheapest solution, so they don't want their processors running any hotter than necessary. AMD is essentially doing the same thing as overclockers do: bumping the voltage to get more speed. The other way to look at it is that all the parts are capable of going fast, so they undervolt the 1700+'s to reduce power.

 

[Peter]

Exactly ... with production yield improvements come a few benefits: Firstly, the average speed grade goes up. Secondly, on the lower end of the speed grade range, the chips can safely run the same speed at a lower voltage.

 

[bibledoc]

in one word, HEAT .... lower voltage less HEAT.. better
more voltage, more heat ... bad....