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Mac Forum / General / Hardware / September 2008Cube G4 ram into eMac 700
Plugging PC100 RAM into a PC133 eMac slot is going to cause no problems? Mark TIA > Plugging PC100 RAM into a PC133 eMac slot is going to cause no problems? Using RAM that's slower than required for a computer is a great way to cause problems. If it even boots up, it's likely to crash, and often.  SignatureI kill Google Groups posts. See http://improve-usenet.org for details. <http://designsbymike.net/shop/mac.cgi> Mac and geek T-shirts & gifts <http://designsbymike.net/shop/prius.cgi> Prius shirts/bumper stickers <http://designsbymike.net/shop/greet.cgi> Holiday cards with attitude > Plugging PC100 RAM into a PC133 eMac slot is going to cause no problems? > > Mark > TIA 2 of the RAM cards are marked PC 100-332-620. Are these safe? Mark > > Plugging PC100 RAM into a PC133 eMac slot is going to cause no problems? > > 2 of the RAM cards are marked PC 100-332-620. Are these safe? I already told you that it's not going to work. If you put PC100 RAM in a machine that requires PC133, if it even boots up, it'll crash left and right. SignatureI kill Google Groups posts. See http://improve-usenet.org for details. <http://designsbymike.net/shop/mac.cgi> Mac and geek T-shirts & gifts <http://designsbymike.net/shop/prius.cgi> Prius shirts/bumper stickers <http://designsbymike.net/shop/greet.cgi> Holiday cards with attitude > > > Plugging PC100 RAM into a PC133 eMac slot is going to cause no problems? > > [quoted text clipped - 3 lines] > a machine that requires PC133, if it even boots up, it'll crash left and > right. Please note, however, that some RAM modules are "switchable" in that they are capable of toggling their speeds based on the requirements the hardware imposes on them. I was very concerned when two 512s I bought from OWC showed up in System Profiler as PC100-3225, but a call to the vendor assured me that they were indeed running at PC133 speeds and I have not experienced any RAM-related crashes (or any other kind either) since I installed them a couple of months ago (1.47 GHz / 1.5 GB G4). Cheers! Mudge SignatureLife is change: How it differs from the rocks! I've seen their ways too often for my liking. New worlds to gain: My life is to survive . . . . . . and be alive for you. > Please note, however, that some RAM modules are "switchable" in that > they are capable of toggling their speeds based on the requirements the [quoted text clipped - 7 lines] > > Mudge Bullshit, Oh how it would be nice if Usenet Posters actually KNEW what they pontificate about..... Ram Speed doesn't "Switch" it is a HARDWARE Propagation Time designed into the Ram chips when they are built. If you have PC100 Chips they WILL function at PC100 Speeds. If you have PC133 Chips, they will function at PC133 speeds, as well as ANY Slower Speed. What the Module says it is, is programmed into a separate memory location, on board the module, and read during Memory Initialization. > > Please note, however, that some RAM modules are "switchable" in that > > they are capable of toggling their speeds based on the requirements the [quoted text clipped - 17 lines] > says it is, is programmed into a separate memory location, on board > the module, and read during Memory Initialization. Well, thanks for your ever-so-pleasant reply, You, but these modules do say PC133 on them, but according to my friends at OWC fail to report it to the System Profiler application, reporting instead to have "toggled" down to PC100. If they were really running at 100 MHz, I'd expect that I'd see the sort of system crashes others have predicted (or at least a noticeable sluggishness in general) but the machine is solid as a rock. If You would like to take it up with the folks at OWC, please feel free to give them a call. Cheers! Mudge SignatureLife is change: How it differs from the rocks! I've seen their ways too often for my liking. New worlds to gain: My life is to survive . . . . . . and be alive for you. >>> Please note, however, that some RAM modules are "switchable" in that >>> they are capable of toggling their speeds based on the requirements the [quoted text clipped - 30 lines] > > Mudge Also I have seen many late production modules marked as PC100 but built with PC133 chips (look at the manufactures data sheets for the chips,) quite often the SPID chip (a tiny 8k flash chip on the end of the module) is programmed with dual timings for PC100 and PC133, also some systems will ignore the SPID settings and run the module at 133 anyway (at least some PC's will, not so sure about Mac's) this was done because the chip makers stopped producing PC100 chips and switched to the backwards compatible PC133, however the market still had a demand for PC100 so lots of PC133 capable modules were sold as PC100. The best thing would be to try them and run either a good memory testing utility for 24 hours or try doing some intensive Photoshop editing for a few hours, this will tell you if the memory will be stable or not. Ben. > Also I have seen many late production modules marked as PC100 but built > with PC133 chips (look at the manufactures data sheets for the chips,) [quoted text clipped - 5 lines] > backwards compatible PC133, however the market still had a demand for > PC100 so lots of PC133 capable modules were sold as PC100. That all makes sense, but let's all not lose sight of the fact that the OP is talking about DIMMs removed from a Cube, so it's likely we have a good idea of when they were manufactured. > The best thing would be to try them and run either a good memory testing > utility for 24 hours or try doing some intensive Photoshop editing for a > few hours, this will tell you if the memory will be stable or not. Great idea. I'd just want to make sure the OP has a reliable backup first, in case there's a hard crash that leads to directory corruption. SignatureI kill Google Groups posts. See http://improve-usenet.org for details. <http://designsbymike.net/shop/mac.cgi> Mac and geek T-shirts & gifts <http://designsbymike.net/shop/prius.cgi> Prius shirts/bumper stickers <http://designsbymike.net/shop/greet.cgi> Holiday cards with attitude > >>> Please note, however, that some RAM modules are "switchable" in that > >>> they are capable of toggling their speeds based on the requirements the [quoted text clipped - 44 lines] > few hours, this will tell you if the memory will be stable or not. > Ben. Thanks for your courteous and well-reasoned reply, Ben. What you have reported squares with what the nice folks at OWC told me. They were a bit embarrassed that the modules I got insist that they are PC100, but assured me I have nothing to worry about, and they've indeed performed flawlessly since I installed them. Cheers! Mudge SignatureLife is change: How it differs from the rocks! I've seen their ways too often for my liking. New worlds to gain: My life is to survive . . . . . . and be alive for you. >> Ram Speed doesn't "Switch" it is a HARDWARE Propagation Time designed >> into the Ram chips when they are built. If you have PC100 Chips >> they WILL function at PC100 Speeds. If you have PC133 Chips, they will >> function at PC133 speeds, as well as ANY Slower Speed. What the Module >> says it is, is programmed into a separate memory location, on board >> the module, and read during Memory Initialization. >Well, thanks for your ever-so-pleasant reply, You, but these modules do >say PC133 on them, but according to my friends at OWC fail to report it >to the System Profiler application, reporting instead to have "toggled" >down to PC100. If they were really running at 100 MHz, I'd expect that >I'd see the sort of system crashes others have predicted (or at least a >noticeable sluggishness in general) but the machine is solid as a rock. >If You would like to take it up with the folks at OWC, please feel free >to give them a call. That's not how it works. First of all, RAM does not care about "Megahertz" at least not directly. They are concerned about time. Take this oversimplifed example.. You need to read a byte of data at address 00FFAA23BAD. Step 1) Push 00FFAA23BAD to the address bus handling such. [Systems can have more than one such bus...] 2) Wait 3) Read the data bus at that address.. You wait, because the address bus takes some time to quiet down, the chip then takes some time to find that data and put in on the data bus, then you want that bus's noise to die down, etc... Better RAM does not take as long for its step; its data is up sooner. So, if your CPU can read it sooner, it's "faster". Now, if you don't read it as fast as you could, but wait a while, as a slower system would, that's OK too. If you waited long enough, the data would eventually bleed away except for refresh... [Dynamic RAM is a series of tubes no wait... it's millions of little capacitors holding a [un]charge. Keeping them correctly [un]charged over time is another aspect called "refresh"....... We talk memory bus speed for the benefit of the humans designing systems. Somewhere there's a spec that gives times for the dozen-plus access times on PC100 vs PC133. I've used PC133 in PC100 systems with no difficulties, but that does not mean it's universally true. SignatureA host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
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