From owner-chemistry@ccl.net Fri Feb 17 08:07:00 2012 From: "Gkourmpis, Thomas Thomas.Gkourmpis : borealisgroup.com" To: CCL Subject: CCL:G: Gaussian on a PC computer Message-Id: <-46320-120217020359-23428-mFLE6bYglsg28FWtt7RFxg__server.ccl.net> X-Original-From: "Gkourmpis, Thomas" Content-Language: en-US Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" Date: Fri, 17 Feb 2012 08:03:46 +0100 MIME-Version: 1.0 Sent to CCL by: "Gkourmpis, Thomas" [Thomas.Gkourmpis{:}borealisgroup.com] Hello According to my chats with the guys in Gaussian the Windows version (what they call multicore) is a 32bit version so is able to use up to 2GB of RAM. The issue with using all the cores in a computer is in essence a matter of how much RAM can the program access, since Gaussian is using a system where the program itself decides how many processors will use. In principle it can use up to 4 but since you're limited by your RAM allocation most times it will use anything between 1 and 3. Also don't forget that the 2GB are total memory, so they're shared between the cores. Therefore in calculations that need a lot of memory like SCFs or frequency you're better off using one or two cores instead of four (the program will do that for you). In all if you want to get top performance from Gaussian either get the Linux version or pressure them to finish up and release the 64bit version for Windows :-) I hope this helps Thomas -----Original Message----- > From: owner-chemistry+thomas.gkourmpis==borealisgroup.com=ccl.net [mailto:owner-chemistry+thomas.gkourmpis==borealisgroup.com=ccl.net] On Behalf Of willsd{:}appstate.edu Sent: Friday, February 17, 2012 2:10 AM To: Gkourmpis, Thomas Subject: CCL:G: Gaussian on a PC computer Sent to CCL by: [willsd(a)appstate.edu] While I am not sure about the windows version, the 64-bit (intel) linux version of G09 I use at my university will certainly use all 8 cores I have on a shared memory node. I think you must use the linda parallel version to run jobs on multiple compute nodes, but I think the normal version requires nothing special to run on shared cores using the same memory space. Steve Williams ----- Original Message ----- > From: "Ronald Cook cookrl(-)tda.com" Date: Thursday, February 16, 2012 7:16 pm Subject: CCL:G: Gaussian on a PC computer To: "Williams, Steve " > Hi Rapha > > I have been running G09W calculations on a Windows XP system using > an Intel > i7-2700K processor. The chip is normally clocked at 3.5GHz, but we > havebeen running calculations for several months now with the system > overclocked at 5GHz with no overheating problems. We see about 30% > decrease in computational time. Furthermore, G09W does not use > hyperthreading. So If you go into the task manager and select > processesand right click on G0W9 and then uncheck processors 4-7 > (which are virtual > anyway) and just use processors 0-3 you can get an additional 30% > decreasein computational time. > > Ron > > On Thu, Feb 16, 2012 at 2:53 PM, Raphael Martinez > raphaelmartinez1983++gmail.com wrote: > > > > > Sent to CCL by: "Raphael Martinez" [raphaelmartinez1983:- > :gmail.com]> Hi everyone: > > If I have an Intel quad core, 16GB ram computer with either linux or > > Windows, does it Gaussian uses all 4 cores if I request to do so > in the > > input file? > > If not, what would be the best processor to have in a personal > computer to > > run Gaussian? > > Thanks > > RaphaI> > > > > > > > -- > Ronald L Cook > Principal Scientist > TDA Research, Inc. > cookrl++tda.com > 303-940-2302http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txtThis Email and any files transmitted with it are confidential and intended solely for the use of the individual or the entity to whom it is addressed. If you have received this Email by error, please notify the sender and delete the material from any storage device. Borealis extends no warranties and makes no representations as to the accuracy or completeness of the information provided. It is the customer's responsibility to inspect and test our products and technical advice in order to satisfy itself as to the suitability of the products and technical advice for the customer's particular purpose.